LIBRARY  OF  THE 
UNIVERSITY  OF  ILLINOIS 
AT  URBANA-CHAMPAIGN 

6 30 

U> o 3 evi 
n.  s. 

no.  61-6  6 
cop.  3 


'NATURAL  HISTORY 
SURVEY 


Digitized  by  the  Internet  Archive 
in  2015 


https://archive.org/details/papersoncottonbo6166unit 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ENTOMOLOGY— BULLETIN  No.  63. 

L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau. 


PAPERS  ON  THE  COTTON  BOIL  WEEVIL  AND 
RELATED  AND  ASSOCIATED  INSECTS. 


CONTENTS  AND  INDEX. 


Issued  July  17,  1909. 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE. 

1909. 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ENTOMOLOGY— BULLETIN  No.  63. 

L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau. 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL  AND 
RELATED  AND  ASSOCIATED  INSECTS. 


I.  HIBERNATION  AND  DEVELOPMENT  OF  THE  COTTON  BOLL  WEEVIL. 

By  E.  DWIGHT  SANDERSON,  Formerly  State  Entomologist  of  Texas. 

II.  NOTES  ON  THE  BIOLOGY  OF  CERTAIN  WEEVILS  RELATED 
TO  THE  COTTON  BOLL  WEEVIL. 

By  W.  DWIGHT  PIERCE,  Special  Field  Agent. 

III.  AN  ANT  ENEMY  OF  THE  COTTON  BOLL  WEEVIL. 

By  W.  E.  HINDS,  In  Charge  of  Cotton  Boll  Weevil  Laboratory. 

IV.  A PREDATORY  BUG  REPORTED  AS  AN  ENEMY  OF  THE 
COTTON  BOLL  WEEVIL. 

By  A.  C.  MORGAN,  Special  Field  Agent. 

V.  NOTES  ON  THE  PEPPER  WEEVIL. 

By  F.  C.  PRATT,  Assistant. 

VI.  THE  STRAWBERRY  WEEVIL  IN  THE  SOUTH-CENTRAL  STATES  IN  1905. 

By  A.  W.  MORRILL,  Special  Field  Agent. 

VII.  THE  COTTON  STALK-BORER. 

By  A.  C.  MORGAN,  Special  Field  Agent. 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE. 

1909. 


BUREAU  OF  ENTOMOLOGY. 


L.  0.  Howard,  Entomologist  and  Chief  of  Bureau. 

C.  L.  Marlatt,  Entomologist  and  Acting  Chief  in  Absence  of  Chief. 

R.  S.  Clifton,  Executive  Assistant. 

C.  J.  Gilliss,  Chief  Cleric. 

F.  H.  Chittenden,  in  charge  of  truck  crop  and  stored  product  insect  investigations. 

A.  I).  Hopkins,  in  charge  of  forest  insect  investigations. 

W.  D.  Hunter,  in  charge  of  southern  field  crop  insect  investigations. 

F.  M.  Webster,  in  charge  of  cereal  and  forage  insect  investigations. 

A.  L.  Quaintance,  in  charge  of  deciduous  fruit  insect  investigations. 

E.  F.  Phillips,  in  charge  of  bee  culture. 

D.  M.  Rogers,  in  charge  of  gipsy  moth  field  work. 

A.  W.  Morrill,  in  charge  of  white  fly  investigations. 

W.  F.  Fiske,  in  charge  of  gipsy  moth  laboratory. 

R.  S.  Woglum,  in  charge  of  hydrocyanic  acid  gas  investigations. 

R.  P.  Currie,  in  charge  of  editorial  work. 

Mabel  Colcord,  librarian. 

Southern  Field  Crop  Insect  Investigations. 

W.  D.  Hunter,  in  charge. 

W.  D.  Pierce,  R.  A.  Cushman,  C.  E.  Hood,  E.  S.  Tucker,  engaged  in  cotton  boll 
weevil  investigations. 

F.  C.  Bishopp,  J.  D.  Mitchell,  H.  P.  Wood,  engaged  in  cattle  tick  life  history  investi- 
gations. 

A.  C.  Morgan,  C.  R.  Jones,  engaged  in  tobacco  insect  investigations. 

I).  L.  Van  Dine,  engaged  in  sugar-cane  and  rice  insect  investigations. 

F.  C.  Pratt,  engaged  in  cactus  insect  investigations. 


IV 


LETTER  OF  TRANSMITTAL 


U.  S.  Department  of  Agriculture, 

Bureau  of  Entomology, 
Washington , D.  C.,  June  10,  1909. 

Sir:  I have  the  honor  to  transmit  herewith,  for  publication  as 
Bulletin  No.  63,  seven  papers  dealing  with  the  cotton  boll  weevil  and 
related  and  associated  insects.  These  papers,  which  were  issued  sep- 
arately during  the  early  part  of  the  year  1907,  are  as  follows:  Hiber- 
nation and  Development  of  the  Cotton  Boll  Weevil,  by  E.  Dwight 
Sanderson;  Notes  on  the  Biology  of  Certain  Weevils  Related  to  the 
Cotton  Boll  Weevil,  by  W.  Dwight  Pierce;  An  Ant  Enemy  of  the 
Cotton  Boll  Weevil,  by  W.  E.  Hinds;  A Predatory  Bug  Reported  as 
an  Enemy  of  the  Cotton  Boll  Weevil,  by  A.  C.  Morgan;  Notes  on  the 
Pepper  Weevil,  by  F.  C.  Pratt ; The  Strawberry  Weevil  in  the  South- 
Central  States  in  1905,  by  A.  W.  Morrill;  The  Cotton  Stalk-Borer, 
by  A.  C.  Morgan. 

Respectfully,  L.  O.  Howard, 

Chief  of  Bureau. 

Hon.  James  Wilson, 

Secretary  of  Agriculture. 


CONTENTS: 


Page. 

Hibernation  and  development  of  the  cotton  boll  weevil . . E.  Dwight  Sanderson . . 1 

Introduction 1 

Hibernation 1 

Date  of  entering  hibernation 1 

Number  of  weevils  entering  hibernation 5 

Development  of  immature  stages  during  normal  period  of  hibernation.  8 

♦ Mortality  of  hibernating  weevils * . . 11 

Time  of  greatest  mortality  during  hibernation 14 

Places  of  hibernation 17 

Time  of  emergence  from  hibernation 19 

Prevention  of  hibernation 22 

Summer  broods  of  the  weevil 25 

Mortality  of  summer  broods . 28 

Rate  of  increase  of  the  weevil 31 

Injury  to  squares  in  relation  to  the  natural  increase  of  squares 33 

Notes  on  the  biology  of  certain  weevils  related  to  the  notton  boll  weevil 

W.  Dwight  Pierce. . . 39 

Introduction ...  39 

Anthonomus  disjunctus  Lee 41 

Anthonomus  fulvus  Lee 41 

Anthonomus  squamosus  Lee 42 

IAxus  musculus  Say ...  43 

Orihoris  crotchii  Lee 44 

An  ant  enemy  of  the  cotton  boll  weevil.  ( Solenopsis  geminata  Fab.  var.  xyloni 

McC.) W.  E.  Hinds..  45 

Introduction 45 

Description 45 

An  enemy  of  the  cotton  leaf- worm  and  bollworm 46 

Its  work  as  an  enemy  of  the  cotton  boll  weevil : 46 

Distribution 48 

A predatory  bug  reported  as  an  enemy  of  the  cotton  boll  weevil.  ( Apiomerus 

spissipes  Say) A.  C.  Morgan..  49 

Introduction 49 

Life  history 49 

Food . . 50 

Length  of  life  cycle 53 

Natural  enemies 54 

Distribution . 54 

Conclusion ........  54 


a The  seven  papers  constituting  this  bulletin  were,  issued  in  separate  form  on  Jan- 
uary 15,  February  5,  February  5,  February  8,  February  9,  January  22,  and  February  9, 
1907,  respectively. 


VII 


VIII  PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 

Page. 

Notes  on  the  pepper  weevil.  ( Anthonomus  xneotinctus  Champ.) . . F.  C.  Pratt . . 55 

Occurrence  in  Texas. 55 

Origin 55 

Food  plants 56 

Natural  enemies 56 

Proliferation 57 

Remedies 58 

The  strawberry  weevil  in  the  South-Central  States  in  1905.  ( Anthonomus  sig- 

natus  Say) A.  W.  Morrill. . 59 

The  strawberry  weevil  in  Texas 59 

The  strawberry  weevil  in  Louisiana 60 

The  strawberry  weevil  in  Arkansas 61 

Varieties  of  strawberries  grown 62 

The  cotton  stalk-borer  (Ataxia  cry pta  Say) A.  C.  Morgan..  63 

Distribution 63 

Host  plants 63 

Life  history 64 

Injury  and  ecor&mic  importance % 64 

Natural  enemies 65 

Remedy 65 

Bibliography 66 


ILLUSTRATIONS. 


PLATES. 

Page. 

'late  I.  Work  of  Lixus  musculus  and  Orthoris  crotchii.  Fig.  1. — Gall  of  Lixus 
musculus  and  exit  hole  of  adult  on  stem  of  Polygonum  pennsyl- 
vanicum.  Fig.  2. — Gall  of  Lixus  musculus  and  entrance  hole 
(closed)  of  pyralid  caterpillar  on  stem  of  Polygonum.  Fig.  3. — 

Pod  of  Mentzelia  nuda  showing  two  egg  punctures  of  Orthoris 
crotchii.  Fig.  4. — Pod  of  Mentzelia  opened,  showing  a cluster  of 
Orthoris  crotchii  cells,  and  the  cocoons  of  Tetrastichus.  Figs.  5, 

6. — Interior  of  pod  of  the  same,  showing  several  cells  of  Orthoris 
•crotchii.  Fig.  7. — An  isolated  cell  of  Orthoris  crotchii , showing  the 

manner  in  which  the  seeds  are  eaten 42 

II.  Work  of  the  pepper  weevil  ( Anthonomus  xneotinctus) . Fig.  1. — 
Emergence  holes  of  adult  in  chilli  pepper.  Fig.  2. — Full-grown 
larvae  in  situ  in  chilli  pepper.  Fig.  3. — Pupae  in  cells  in  chilli  pep- 
per, Fig.  4. — Undeveloped  bell-pepper  pod,  showing  numerous 
egg  and  feeding  punctures.  Figs.  5,  6. — Malformed  bell-pepper 
pods  caused  by  egg  punctures 56 

III.  The  cotton  stalk-borer  ( Ataxia  crypta).  Fig.  1.— Adult  or  beetle. 

Fig.  2. — a,  Galleries;  b,  work.  Fig.  3. — Emergence  holes  of 
adults.  Fig.  4. — a,  Larva  in  situ ; b,  pupa  in  situ.  Fig.  5. — a,  Gal- 
lery running  into  root  of  plant  ; b,  castings  behind  larva 64 

TEXT  FIGURES. 

ig.  1.  Daily  temperatures  at  College  Station,  Tex.,  October  1,  1903,  to  June 

15,1904 4 

2.  Rainfall  and  temperature  records  for  College  Station  and  Victoria, 

Tex.,  in  1903-4,  compared  with  normals : . . 5 

3.  Rainfall  and  temperature  records  of  College  Station  and  Victoria,  Tex., 

for  1902-3,  compared  with  normals 13 

4.  Rainfall  and  temperature  records,  Hallettsville,  Tex.,  1899-1901,  com- 

pared with  normals  for  each  year 15 

5.  Rainfall  and  temperature  records,  Hallettsville,  Tex.,  1902-1904,  com- 

pared with  normals  for  each  year 16 

6.  Comparison  of  normal  temperatures,  October  15  to  June  15,  for  various 

districts  in  Texas 20 

7.  An  ant  enemy  of  the  cotton  boll  weevil:  Cotton  squares  showing  emer- 

gence hole  of  weevil  and  entrance  holes  of  Solenopsis  geminata  var. 

xyloni  for  comparison 47 

8.  Apiomerus  spissipes:  Adult,  egg  mass,  nymph 50 

9.  Apiomerus  spissipes:  Egg 50 

10.  The  pepper  weevil  {Anthonomus  xneotinctus) : Adult 56 


IX 


INDEX. 


Page. 

cer  negundo,  food  plant  of  Ataxia  crypia 64 

labama  argillacea.  ( See  Leaf-worm,  cotton.) 

mbrosia,  food  plant  of  Ataxia  crypta 63,  64 

nt  enemy  of  boll  weevil 45-48 

nthonomus  aeneolus,  host  of  Catolaccus  incertus. 40 

on  Solanum  rostratum 40 

aeneotinctus 55-58 

enemies 56-57 

food  for  Apiomerus  spissipes 51, 52,  54 

Sinea  diadema 51, 52,  54 

plants 39,  56 

influence  of  proliferation 57 

in  Texas 55 

origin 55-56 

remedies 58 

disjunctus,  habits 41 

on  Heterotheca  subaxillaris , 40, 41 

parasites 41 

Julvus,  habits 41-42 

host  of  Bracon  mellitor. . 40, 41 

on  Callirrhoe  involucrata 40, 41-42 

grandis  ( see  also  Boll  weevil). 

as  food  for  Apiomerus  spissipes 51,  52,  54 

Sinea  diadema 51,  52 

host  of  Bracon  mellitor 40, 47 

Eurytoma  tylodermatis 40 

on  cotton 39 

search  for  parasites 59 

scutellaris,  on  wild  plum  in  Texas. . . 40 

signatus , food  plants 39,  60 

in  Arkansas 61 

Louisiana] 60 

South-Central  States  in  1905 59-62 

Texas 59-60 

squamosus,  habits 42-43 

host  of  Bracon  mellitor 40,  43 

Eurytoma  tylodermatis 40,43 

on  Grindelia  squarrosa  nuda 40, 42-43 

parasites 43 

Aphis,  cotton.  (S ee  Aphis  gossypii.) 

gossypii,  not  proper  food  for  Apiomerus  spissipes 52 

Apiomerus  spissipes,  cannibalism 53 

copulation 49 

distribution 54 

i einr  49—50 


68 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


Apiomerus  spissipes,  enemies : 

enemy  of  boll  weevil . 

food 

incubation 

length  of  life  cycle. . . 

life  history 

oviposition 

Apion,  eaten  by  Apiomerus  spissipes 

Apricot,  food  plant  of  Ataxia  crypta 

Ataxia  crypta 

bibliography 

distribution 

economic  importance 

enemies 


61 


host  plants ...  

life  history 

remedy 

sordida,  bibliographic  reference 

Bees,  eaten  by  Apiomerus  spissipes 

Blackberry,  food  plant  of  Anthonomus  signatus 

Boll  weevil  (see  also  Anthonomus  grandis). 

ant  enemy,  Solenopsis  geminata  xyloni 

biology  of  related  weevils,  notes 

bug,  predatory,  enemy 

control  by  crop  rotation 

early  planting,  explanation 

fall  destruction  of  stalks 7, 


6< 

61 


51 

31 


4 l 
31 
41 


grazing 

leaf- worm 

planting  early  varieties  of  cotton 

Solenopsis  geminata  xyloni 

development  of  immature  stages  during  normal  period  of  hiberna- 
tion  


d 


a 


hibernation  and  development II 

as  affected  by  rainfall 5— 6l 

temperature 3— 6| 

condition  of  immature  stages I 

emergence,  time 191 


entrance,  date I 

mortality  in  cages I 

the  field Ill 


time  when  greatest. 


Ml 


places. 


1/1 

of  first  appearance  after  emergence 241 

prevention I 

increase,  rate 311 

mortality  at  different  stages  of  development I 

during  hibernation,  in  cages I 

the  field Ill 

time  when  greatest 14| 

in  buried  squares I 

of  summer  broods 2b| 


INDEX. 


69 


Page. 

1 weevil,  percentage  emerging  from  infested  squares - - 28 

places  of  first  appearance  after  emergence  from  hibernation 

preyed  upon  by  Apiomerus  spissipes . 

progress  of  infestation  compared  with  production  of  cotton  fruit. . . 88-88 

summer  broods 

mortality d 

lworm,  preyed  upon  by  Solenopsis  geminata  xyloni 4^ 

t elder.  (See  Acer  negundo.) 

con  mellitor , parasite  of  Anthonomus  xneotinctus 

fulvus 40’41 

grandis - 40,47 

squamosus 40,  43 

y,  predatory,  reported  enemy  of  boll  weevil 4^  ^4 

rning  of  stalks  in  control  of  boll  weevil ao  41-49 

'.lirrhoe  involucrata,  food  plant  of  Anthonomus  fulvus 40,  41-4Z 

mibalism  in  Apiomerus  spissipes 

\olaccus  incertus,  parasite  of  Anthonomus  xneolus 

xneotinctus ^ 

sp.,  parasite  of  Anthonomus  squamosus — 4^ 

ndomyiid  gall-maker,  eaten  by  Apiomerus  spissipes ^3 

'ambycobius  cyaneiceps,  parasite  of  Lixus  musculus. 

tton  aphis.  (See  Aphis  gossypii.) 

boll  weevil.  ( See  Boll  weevil  and  Anthonomus  grandis.) 

early  varieties  to  avoid  damage  from  boll  weevil,  explanation 38 

planting  to  avoid  damage  from  boll- weevil,  advantage  explained . . 38 

fall  destruction  of  stalks  in  boll-weevil  control ^ 

food  plant  of  Anthonomus  grandis y 

Ataxia  crypta ’ 

leaf- worm.  (See  Leaf-worm,  cotton.) 

squares,  injury  from  boll  weevil  in  relation  to  natural  increase  of  squares . 88-88 
stalk-borer.  (See  Ataxia  crypta.) 

varieties,  production  of  fruit ^ ^ 

yield ” 7 

yield  at  College  Station,  Tex.,  m 1904 ^ 

op  rotation  in  control  of  boll  weevil 

lcumber  beetle,  twelve-spotted.  (See  Diabrotica  12-punctata.) 

lltural  experiments  in  control  of  pepper  weevil " 

esmoris  scapalis  on  Sideranthus  rubiginosus - 

evelopment  of  boll  weevil  during  normal  period  of  hibernation 8- 

ewberry,  food  plant  of  Anthonomus  signatus ™ 

iabrotica  12-punctata,  eaten  by  Apiomerus  spissipes * " 

'troxys  sp.,  parasite  of  Ataxia  crypta 

'urytoma  tylodermatis , parasite  of  Anthonomus  grandis 

squamosus 40,  48 

Lixus  musculus 40,  43 

all  destruction  of  stalks  in  control  of  boll  weevil ^ 

'ig,  food  plant  of  Ataxia  crypta ^ 

Fire-ant,”  name  for  Solenopsis  geminata 

lies,  house,  eaten  by  Apiomerus  spissipes - - - ’ 

bod  supply  as  controlling  numbers  of  boll  weevil  in  the  fall 

Uyptomorpha  rugator,  parasite  of  Lixus  musculus - - - - 

hazing,  factor  in  control  of  boll  weevil — 

Trindelia  squarrosa  nuda,  food  plant  of  Anthonomus  squamosus. ’ 


70 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


Hackberry,  food  plant  of  Ataxia  crypta 

Hadronotus  n.  sp.,  parasite  of  Apiomerus  spissipes 

Helianthus,  food  plant  of  Anthonomus  squamosus 

Ataxia  crypta 

Heterospilus  websteri , parasite  of  Ataxia  crypta , 

Heterotheca  subaxillaris,  food  plant  of  Anthonomus  disjunctus 4^ 

Hibernation  of  boll  weevil,  as  affected  by  rainfall 5_^ 

temperature 3-6 

condition  of  immature  stages 

development  of  immature  stages  during  normal 

period g. 

emergence,  time j 19. 

entrance,  date /. 

mortality  in  cagejs \ 


the  field 

time  when  greatest 

number  entering 

places 

of  first  appearance  after  emergence 

prevention 

Hinds,  W.  E.,  paper,  “An  Ant  Enemy  of  the  Cotton  Boll  Weevil  ( Solenopsis 

geminata  Fab.  var.  xyloni  McC.)” 

Homalodisca  triquetra,  refused  by  Apiomerus  spissipes 

“Hormiga  brava,  ” Spanish-American  name  for  Solenopsis  geminata 

Increase  of  boll  weevil,  rate 

Ladybirds,  eaten  by  Apiomerus  spissipes 

Lamia  crypta , bibliographic  reference i 

— Ataxia  crypta 

Leaf-worm,  cotton,  factor  in  control  of  boll  weevil 

preyed  upon  by  Solenopsis  geminata  xyloni 

Leptinotarsa  decemlineata , refused  by  Apiomerus  spissipes 

Lixus  musculus,  habits 

host  of  Eurytoma  tylodermatis 

parasites 

Locusts,  eaten  by  Apiomerus  spissipes 

Mentzelia  nuda,  food  plant  of  Orthoris  crotchii 

Microbracon  ( Bracon ) nuperus,  parasite  of  Orthoris  crotchii 

Morgan,  A.  C.,  paper,  “A  Predatory  Bug  Reported  as  an  Enemy  of  the  Cotton 

Boll  Weevil  ( Apiomerus  spissipes  Say)  ” 

“The  Cotton  Stalk-Borer  ( Ataxia  crypta  Say)  ” 

Morrill,  A.  W.,  paper,  “The  Strawberry  Weevil  in  the  South-Central  States  in 

1905  ( Anthonomus  signatus  Say)  ” 

Mortality  of  boll  weevil  at  different  stages  of  development 

hibernating  in  cages 


11- 

14r 


17- 

24r 


45- 


31- 


43- 

40, 


49-, 

63-i 


59-i 

2 


the  field 11- 

in  buried  squares 

summer  broods 28- 

time  when  greatest  during  hibernation 14- 

Neocatolaccus  tylodermx , parasite  of  Lixus  musculus 

Orthoris  crotchii , habits * 


parasites 

Peach,  food  plant  of  Ataxia  crypta 

Pentatoma  ligata , not  proper  food  for  Apiomerus  spissipes 


( 


INDEX. 


71 


Page. 

Pepper,  bell  or  sweet,  chilli,  and  tabasco  varieties,  food  plants  of  Anthonomus 

seneotinctus - 56 

food  plant  of  Anthonomus  seneotinctus. 39,  56 

proliferation 57 

weevil.  (See  Anthonomus  seneotinctus.) 

wild  or  bird,  not  food  plant  of  Anthonomus  seneotinctus 56 

Pierce,  W.  Dwight,  paper,  “Notes  on  the  Biology  of  Certain  Weevils  Related  to 

the  Cotton  Boll  Weevil  ” 39-44 

Plowing  out  in  control  of  boll  weevil 7 

Plum,  wild,  food  plant  of  Anthonomus  scutellaris 40 

YPolygonum  pennsylvanicum , food  plant  of  Lixus  musculus 43 

Potato  beetle.  (See  Leptinotarsa  decemlineata.) 

Pratt,  F.  C.,  paper,  “Notes  on  the  Pepper  Weevil  ( Anthonomus  seneotinctus 

Champ.)” 55-58 

Rainfall  as  affecting  hibernation  of  boll  weevil 5-6, 13 

Redbud,  food  plant  of  Anthonomus  signatus 39 

Sanderson,  E.  Dwight,  paper,  “Hibernation  and  Development  of  the  Cotton 

Boll  Weevil” 1-38 

Sharpshooter.  (See  Homalodisca  triquetra.) 

Sideranthus  rubiginosus , food  plant  of  Desmoris  scapalis 40 

Sinea  diadema , food 51,  52 

Solanum  rostratum , food  plant  of  Anthonomus  seneolus 40 

Solenopsis  geminata , enemy  of  Anthonomus  seneotinctus 56 

xyloni,  description 45 

distribution 48 

enemy  of  boll  weevil 45-48 

cotton  leaf-worm  and  bollworm 46 

Stalk-borer,  cotton.  (See  Ataxia  crypta.) 

Strawberry,  food  plant  of  Anthonomus  signatus 39,  60 

varieties  grown  in  South-Central  States 62 

weevil.  (See  Anthonomus  signatus .) 

Temperature  as  affecting  hibernation  of  boll  weevil 3-6, 13 

time  of  emergence  of  boll  weevil  from  hibernation. . . 19-20 

Tetrastichus  sp.,  parasite  of  Orthoris  crotchii 44 

Thrips,  eaten  by  Apiomerus  spissipes 53 

Triphleps  insidiosus , eaten  by  Apiomerus  spissipes 53 

Wasps,  eaten  by  Apiomerus  spissipes 51 

Xanthium,  food  plant  of  Ataxia  crypta 63 

o 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BDREAC  OF  ENTOMOLOGY— BULLETIN  NO.  63,  Part  I. 

L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau. 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL  AND 
RELATED  AND  ASSOCIATED  INSECTS. 


HIBERNATION  AND  DEVELOPMENT  OF  THE 
COTTON  BOLL  WEEVIL. 


BY 


E.  DWIGHT  SANDERSON, 


Formerly  Slate  Entomologist  of  Texas. 


Issued  January  15,  1907. 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE. 

1907. 


LETTER  OF  TRANSMITTAL. 


U.  S.  Department  of  Agriculture, 

Bureau  of  Entomology, 
Washington , D.  6V,  September  15 , 1906. 

Sir:  I have  the  honor  to  transmit  herewith  the  manuscript  of  a cor 
tribution  by  Prof.  E.  Dwight  Sanderson  on  the  hibernation  an 
development  of  the  cotton  boll  weevil.  This  paper  embodies  til 
results  of  a large  amount  of  work  carried  on  by  Professor  Sandersol 
while  State  entomologist  of  Texas,  and  was  written  by  him  in  the  fan 
of  1904.  In  view  of  its  practical  bearing  and  the  fact  that  much  cl 
the  data  it  contains  is  new,  I recommend  its  publication  as  Part  I cl 
Bulletin  No.  63  of  this  Bureau,  the  bulletin  as  a whole  to  be  entitle! 
“Papers  on  the  Cotton  Boll  Weevil  and  Related  and  Associate 
Insects,”  and  to  be  made  up  of  separate  papers  by  various  persor 
engaged  in  cotton  boll  weevil  investigations. 

Respectfully, 

F.  H.  Chittenden, 

Acting  Chief  of  Bureau.  ' 


lion.  James  Wilson, 

Secretary  of  Agriculture. 


CONTENTS. 


introduction - 

Hibernation 

Date  of  entering  hibernation 

Number  of  weevils  entering  hibernation 

Development  of  immature  stages  during  normal  period  of  hibernation 

Mortality  of  hibernating  weevils 

Time  of  greatest  mortality  during  hibernation 


Places  of  hibernation 

Time  of  emergence  from  hibernation 

Prevention  of  hibernation 

Fall  destruction  of  stalks 

Crop  rotation 

Where  the  weevils  first  appear  . 

Summer  broods  of  the  weevil 

Mortality  of  summer  broods 

Rate  of  increase  of  the  weevil 


Injury  to  squares  in  relation  to  the  natural  increase  of  squares 


Page. 

1 

1 

1 

5 

8 

IP 

14 

17 

19 

22 

22 


24 


24 

25 
28 
31 


33 


hi 


ILLUSTRATIONS. 


TEXT  FIGURES. 

Page. 

Fig.  1.  Daily  temperatures  at  College  Station,  Tex.,  October  1,  1903,  to  June 

15,1904 4 

2.  Rainfall  and  temperature  records  for  College  Station  and  Victoria  in 

1903-4,  compared  with  normals 5 

3.  Rainfall  and  temperature  records  of  College  Station  and  Victoria, 

Tex.,  for  1902-3,  compared  with  normals .y 13 

4.  Rainfall  and  temperature  records,  Hallettsville,  Tex.,  1899-1901,  com- 

pared with  normals  for  each  year 15 

5.  Rainfall  and  temperature  records,  Hallettsville,  Tex.,  1902-1904,  com- 

pared with  normals  for  each  year 16 

6.  Comparison  of  normal  temperatures,  October  15  to  June  15,  for  various 

districts  in  Texas 20 


IV 


J.  S.  D.  A.,  B.  E.  Bui.  63,  Part  I.  C.  B.  W.  I.,  January  15,  1907. 

PAPERS  ON  THE  COTTON  BOLL  WEEVIL  AND 
RELATED  AND  ASSOCIATED  INSECTS. 


HIBERNATION  AND  DEVELOPMENT  OF  THE  COTTON  BOLL  WEEVIL. 

By  E.  Dwight  Sanderson, 

Formerly  State  Entomologist  of  Texas. 

INTRODUCTION. 

The  most  economical  method  of  controlling*  the  boll  weevil  is  to 
destroy  its  food  supply  by  burning  or  grazing  the  green  cotton  stalks 
in  the  fall  before  frost  occurs,  so  as  to  reduce  by  starvation  the  num- 
bers which  go  into  hibernation.  As  it  is  known  that  a large  proportion 
of  weevils  die  during  hibernation*  it  may  be  readily  understood  that  a 
much  greater  degree  of  benefit  may  be  derived  by  destroying  the  weevils 
in  the  fall  than  by  attempting  to  destroy  them  in  the  spring.  The  time 
at  which  the  weevils  enter  hibernation,  the  numbers  which  attempt  to 
hibernate,  the  mortality  occurring  during  the  winter  and  the  factors 
which  influence  this  mortality,  and  the  time  of  emergence  in  the  spring 
are,  therefore,  matters  of  practical  importance  upon  which  we  have 
made  careful  observations. 

HIBERNATION. 

DATE  OF  ENTERING  HIBERNATION. 

! 

Table  I gives  a summary  of  eight  lots  of  weevils  which  were  con- 
I fined  in  cages  at  different  dates  during  October  and  November,  1903. 
Altogether  some  1,300  weevils  were  used  in  these  experiments.  Begin- 
ning with  October  7 one  cage  was  started  each  week  until  November 
17.  On  November  18  a sharp  freeze  occurred,  and  almost  immediately 
thereafter  all  weevils  went  into  hibernation.  It  will  be  seen  that  in 
lots  1,  2,  and  3 all  of  the  weevils  died  prior  to  November  18.  During 
the  beginning  of  these  experiments  a plentiful  supply  of  squares  was 
furnished  the  weevils  for  food,  but  as  they  showed  an  inclination 
toward  hibernating  about  the  third  week  in  October  this  supply  was 
discontinued.  In  all  cases  the  weevils  which  hibernated  successfully 

l 


2 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


did  not  begin  hibernation  until  about  November  17  or  18.  This  was 
also  true  of  other  weevils  under  observation  in  the  laboratory.  The 
daily  notes  concerning  one  or  two  of  the  outdoor  cages  started  in  Octo- 
ber are  of  interest  in  this  connection.  For  example,  lot  3 comprized 
100  weevils  put  in  hibernation  cage  with  food  October  16.  The  hiber- 
nation cages  were  wooden  boxes  2 feet  high  and  1 foot  square,  with 
the  sides  about  one-half  open  and  covered  with  wire  window  screening, 
except  the  front,  which  was  of  glass.  In  the  bottom  of  each  cage  was 
placed  plenty  of  rubbish,  consisting  of  fallen  cotton  leaves,  rotten 
wood,  etc.  The  weevils  were  thus  exposed  to  the  outside  temperature, 
but  were  largely  protected  from  rain.  These  cages  were  placed  in 
various  situations  in  a small  grove  and  pasture  at  the  apiary  of  the 
Agricultural  and  Mechanical  College,  College  Station,  Tex.  The  rec- 
ords kept  of  this  lot  and  of  lot  2 are  as  follows: 

October  17,  18,  no  hibernation,  weevils  active;  October  19,  same,  quiet  in  bottom 
of  cage;  October  21,  sign  of  hibernation  evident,  some  weevils  congregate  about  dead 
rubbish  on  floor  of  cage;  October  22,  23,  24,  similar  conditions,  some  seem  to  be  hiber- 
nating; October  25,  a few  more  in  hibernating  attitude;  October  26,  weevils  are 
undoubtedly  hibernating,  shown  by  dormant  attitude  under  rubbish;  October  27, 
about  all  hibernating — if  they  were  let  out  they  would  not  hibernate,  as  some  were 
let  out,  and  they  joined  those  in  the  field  and  commenced  feeding;  October  29,  hoi 
day  arouses  weevils  to  activity;  October  30,  think  weevils  die  at  the  rate  of  1 to  4 pei 
day. 

November  2,  warm  weather  makes  them’ exceedingly  active;  this  continues  until 
the  8th,  when  cool  weather  checks  their  activity;  November  15,  all  weevils  dead. 

Lot  2. — One  hundred  weevils  placed  in  cage  October  8 and  fed  with  squares;  Octo- 
ber 9,  weevils  lively,  flying  about  in  cage;  October  10,  11,  no  signs  of  hibernation 
October  12,  less  active;  October  13,  those  on  rubbish  dead  or  dying;  October  14,  nc 
signs  of  hibernation;  October  18-23,  weevils  active,  no  hibernation;  October  25,  al 
but  8 dead,  those  hibernating  under  rubbish;  October  29,  weevils  active;  Octobei 
29-31,  November  1,  2,  sluggish;  November  5,  all  dead. 


Table  I. — Percentage  of  mortality  of  hibernating  weevils. 


Lot. 

Date  placed  in 
cage. 

Number  of  wee- 
vils. 

Date  hi- 
bernated. 

To  November  18, 1903. 

November 
18-30,  1903. 

December,  1903. 

Died  in  Decem- 
ber. 

Date. 

Alive. 

Dead. 

Date. 

Alive. 

c3 

a> 

ft 

o3 

« 

Alive. 

'd 

c3 

0) 

bi 

K 

jn 

Total  De- 
cember!. 

Per 

Per 

Pa- 

Pa- 

Per 

Per 

Pa- 

Pa- 

1903. 

ct. 

ct. 

ct. 

ct. 

ct. 

ct. 

ct. 

ct. 

1 

October  7 

100 

Nov.  1 

100.0 

I Oct.  24 

a 2 

October  8 

!Oct.  25 

92. 0 

100 

)Nov.  3 

99.0 

(Nov.  5 

100.0 

« 3 

October  16 

100 

/Oct.  30 

(6) 

|Nov.  15 

100.0 

4 

October  23 

100 

Nov.  18 

Nov.  18 

100. 0 

14 

7 

71 

22 

71-i- 

71 

5 

October  25 

....do... 

9.0 

J 4 

67 

33  , 

)- 

82 

71 

a 6 

November  1 . . . 

200 

....do... 

50.0 

'50.0 

23 

50 

50 

\26 

27 

18 

14 

82 

61 

25 

61  + 

11 

7 

November  9 . . . 

200 

....do ... 

Nov.  15 

93.5 

6.5 

8 

November  17.. 

200 

....do... 

25 

100 

:::: 

5+7  ! 

Average . . . 

.,nu 

....do  ... 

8.0 

1 

“I 

4,5,6  , 

Average . . . 

000 

....do  ... 

21.0 

. . . J 

75  + 

51-1 

1 | 

1 

I 

« Furnished  with  squares  for  food. 


b One  to  4 dying  per  day. 


HIBERNATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL. 


3 


Table  I. — Percentage  of  mortality  of  hibernating  weevils — Continued. 


Lot. 

Date  placed  in 
cage. 

Number  of  J 
weevils. 

Date  hi- 
bernated. 

February,  1904. 

March,  1904. 

Total  sur- 
vived. 

Date  active. 

Date. 

Alive. 

Dead. 

Date. 

Alive. 

Dead. 

1 
a 2 
« 3 

4 

5 
a 6 

8 

5+7 
4, 5, 6 

1903. 
October  7 

100 

100 

100 

100 

300 

200 

200 

200 

500 

600 

Per  cl. 

Per  ct. 

Per  ct. 

Per  ct. 

Per  ct. 

Mar.  22 
Mar.  18 

October  8 

October  16 

Or+.nhpr  93 

Nov.  18 
....do... 
....do... 
do 

(b) 

2 

(b) 

October  25 

November  1 . . 
November  9 . . 
November  17  . 

Average . . 
Average . . 

7.3 

91.6 

22 

5.6 

94.4 

5.6 

21 

24 

10.5 

7.0 

89.5 

93.0 

....do ... 

7.0 

.. ..do ... 

6.2 

do  . . . 

a Furnished  with  squares  for  food.  b Accidentally  disturbed  and  discontinued. 


It  will  be  seen  from  these  experiments  that  weevils  can  not  be  forced 
into  hibernation  before  the  temperature  declines  to  that  point  at  which 
the}7  normally  hibernate,  and  that  if  deprived  of  food  or  confined  much 
before  that  time  most  of  them  will  die.  The  first  weevils  to  go  into 
hibernation  were  those  of  lot  4,  placed  in  cages  on  October  23,  but 
these  did  not  actually  hibernate  until  November  18.  The  case  of  lot 
8,  of  200  weevils  placed  in  a cage  November  IT,  in  which  all  died  by 
November  25,  is  difficult  to  explain.  Our  notes  upon  the  condition 
of  the  weevils  in  the  fields  during  the  same  fall  show  practically  the 
same  conditions  as  those  existing  in  the  cages.  The  very  careful 
record  by  Mr.  A.  F.  Conradi,  made  in  fields  in  the  neighborhood  of 
}the  college,  is  briefly  as  follows: 

September  6,  7,  abundant,  very  few  perfect  squares,  dry  weather;  September  8,  9, 
abundant,  mating  pairs  common;  September  10,  abundant,  practically  all  squares 
punctured,  mating  pairs  less  common;  September  11,  12,  less  numerous,  fewer  mating 
pairs,  few  perfect  squares;  September  13,  less  abundant,  perfect  squares  more  com- 
mon, mating  pairs  scarce;  September  14,  15,  less  abundant,  perfect  squares  more 
common;  September  16-18,  fewer  weevils,  perfect  squares  more  common;  Septem- 
ber 19,  less  destructive  than  at  any  time  since  the  10th,  perfect  squares  abundant; 
September  20-28,  similar  conditions;  September  29,  30,  conditions  growing  worse, 
more  weevils,  fewer  perfect  squares;  October  5,  numerous,  eating  vigorously;  Octo- 
ber 10,  exceedingly  abundant  and  destructive,  a few  dozen  perfect  squares  found 
with  great  difficulty,  smallest  squares  often  punctured  in  several  places;  October  11, 
'abundant,  several  on  plants  near  field,  one  in  door  yard  on  house,  mating  common; 

! October  12,  13,  abundant,  few  mating,  few  perfect  squares;  October  14,  many  weevils 
I found  clustering  about  the  base  of  bolls  of  all  sizes  just  inside  of  the  involucre,  no 
signs  of  hibernation;  October  16,  100  weevils  found  on  95  plants  in  thirty  minutes; 
October  18, 19,  weevils  more  sluggish,  unusual  numbers  congregate  behind  involucres 
of  larger  squares;  October  20,  the  size  of  weevils  is  exceedingly  variable,  more  so  than 
at  other  seasons,  general  depression  in  activity;  October  22,  some  adults  mating,  no 
(signs  of  hibernating;  October  23-26,  less  numerous,  no  mating  pairs,  weather  cool, 
jbeetles  seem  to  be  leaving;  November  2,  abundant  in  certain  localities  in  the  field ; 
;.on  5 plants  they  average  one  to  a square,  then  for  a dozen  or  more  none  are  found; 
I mating  common,  but  little  egg  laying  for  several  days. 

9223— No.  63,  pt  1-07- — ■ 2 


4 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


October  3,  weather  warm,  weevils  that  had  assumed  a hibernating  attitude  lively 
again,  mating  pairs  and  oviposition  common;  October  4,  much  more  active,  mating 
pairs  and  number  of  eggs  increasing,  collected  100  weevils  from  132  stalks;  October 
6,  conditions  similar  to  middle  of  September,  collected  50  weevils  from  46  stalks; 
October  7,  weevils  numerous,  mating  common,  more  egg  punctures,  collected  100 
weevils  from  92  stalks  and  67  from  80  stalks;  October  9,  at  apiary,  100  weevils  on 
98  stalks  at  east  end,  50  on  100  stalks,  west  end,  48  on  90  stalks  at  the  middle  of  the 
field;  October  11,  90  weevils  on  176  stalks;  October  13,  average  of  1 weevil  to  2 


x 

a> 

H 


S 

Em 


stalks;  October  15, 16,  weevils  active,  eggs  common;  October  17-21,  low  temperature, 
with  sharp  freeze  on  the  night  of  the  18th,  when  the  cotton  froze  and  the  supply  of  [ 
food  was  exhausted;  October  22,  after  the  18th  weevils  went  into  hibernation  rapidly,  I 
but  diminution  not  markedly  noticed  until  the  22d,  when  there  was  but  1 to  10  i 
stalks. 


The  weevils  were  not  injured  by  the  freeze  of  the  18th,  as  many  I 

were  found  in  the  field  on  the  19th.  By  referring  to  figure  1,  giving). 

' 


HIBERNATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL. 


5 


the  daily  temperature, a it  will  be  seen  that  the  activity  of  the  weevils 
corresponds  very  closely  with  the  rise  and  fall  in  temperature.  Hunter 
and  Hinds6  state  that  hibernation  will  commence  as  the  mean  average 
temperature  falls  to  between  55°  and  60°  F.,  which  our  observations 
of  last  fall  corroborate.  They  also  state  that  at  Victoria  hibernation 
will  normally  commence  about  Decern ber  1.  By  referring  to  figure  2 
it  will  be  seen  that  the  normal  temperature  at  Victoria  drops  to  60°  at 
about  December  1 and  at  College  Station  from  November  10  to  15.  At 
Dallas  hibernation  would  be  several  days  earlier  and  for  northeastern 
Texas  generally  about  November  1 to  10.  From  the  observations 
available,  therefore,  it  would  seem  safe  to  assert  that  hibernation  will 
usually  occur  when  the  mean  average  temperature  drops  below  60°  F. 


Fig.  2. — Rainfall  and  temperature  records  for  College  Station  and  Victoria  in  1903-4  compared  with 

normals. 


NUMBER  OF  WEEVILS  ENTERING  HIBERNATION. 

The  number  of  weevils  found  in  an  infested  field  in  the  fall  at  about 
the  time  hibernation  would  normally  begin  is  governed  largely  by  the 
food  supply  and  is  influenced  also  by  the  temperature  and  rainfall 
during  September  and  October. 

a Concerning  the  method  of  plotting  the  curves  it  should  be  stated  that  the  vertical 
lines  upon  which  the  nodes  of  the  curve  occur  are  marked  as  being  the  15th  of  the 
month.  The  mean  temperature  as  given  by  the  Weather  Bureau  is  reported  at  the 
end  of  each  month.  If  we  should  consider  the  node  of  the  curve  as  occurring  at 
the  end  of  the  month,  we  would  misrepresent  the  facts,  as  during  the  spring  and  fall 
the  temperature  is  on  a gradual  rise  or  decline.  Consequently  if  the  mean  monthly 
temperature  is  given  for  the  15th  of  the  month,  the  exact  temperature  for  dates 
between  these  nodes  can  be  more  correctly  ascertained  from  the  curve.  This  applies 
also  to  the  figures  showing  rainfall. 

&Bul.  45,  Div.  Ent.,  U.  S.  Dept.  Agric.,  p.  81. 


6 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


If  during  September  and  early  October  there  should  be  a normal  or 
excessive  rainfall  and  the  plants  keep  growing,  there  will  be  plenty  of 
squares  upon  which  the  weevils  may  breed  and  multiply  until  frost 
occurs.  If,  on  the  other  hand,  during  this  period  the  weather  should 
be  hot  and  dry,  the  plants  will  stop  growing  and  those  infested  squares 
which  fall  to  the  ground  will  be  quickly  dried  up  and  but  a relatively 
small  number  of  weevils  will  be  produced.  This  was  strikingly  shown 
in  observations  upon  the  number  of  weevils  on  cotton  at  the  college  in 
the  fall  of  1903  as  compared  with  the  fall  of  1901.  During  Septem- 
ber, 1904,  there  was  an  average  of  not  over  3 squares  to  a plant, 
whereas  in  September,  1903,  there  was  an  average  of  about  40  squares 
to  a plant.  At  this  time  during  these  two  seasons  there  was  approxi- 
mately the  same  number  of  weevils  in  the  field;  but  it  can  be  readily 
seen  that  with  so  few  squares  in  which  to  breed,  in  September,  1904, 
there  would  be  far  fewer  weevils  developed  after  September  to  go  into 
hibernation. 

Mr.  Louis  Teltschick  states  that  in  Lavaca  County,  Tex.,  at  the  time 
he  turned  cattle  in  to  graze  his  cotton,  October  17,  1903,  there  were 
about  2 weevils  to  a stalk.  Concerning  this  he  writes  as  follows: 

I will  state  in  this  connection  that  in  my  opinion  the  bulk  of  the  weevils  had  then 
left  the  cotton.  I think  that  during  the  last  three  years  the  majority  of  weevils 
began  leaving  the  cotton  as  early  as  September  1.  They  were  undoubtedly  com- 
pelled to  do  this  by  a scarcity  of  squares.  To  be  more  explicit  I give  you  the  follow- 
ing figures:  On  August  28,  1904,  I estimated  the  number  of  weevils  in  my  field  at  12 
per  stalk.  While  I made  no  such  estimate  in  1902  or  1903,  considering  the  extent  of 
the  injury  worked  by  them  in  those  years,  I think  that  their  numbers  on  the  same 
date  might  safely  be  put  at  6 for  1902  and  9 for  1903.  When  I cut  the  stalks  early  in 
October,  1902,  I found  that  there  were  about  II  weevils  per  stalk,  and  in  October,  . 
1903,  when  I turned  the  cattle  in,  there  were  about  2 weevils  per  stalk.  You  will  see 
that  according  to  these  estimates  from  75  to  80  per  cent  of  the  weevils  infesting  the 
fields  on  August  28  in  those  years  had  disappeared  by  October  15,  leaving  out  of 
account  all  weevils  hatched  between  the  two  dates.  Where  they  went  or  what  be- 
came of  them  I am  unable  to  say.  They  may  have  gone  to  uninfested  regions,  or 
they  may  have  died  or  gone  into  hibernation  quarters  when  squares  became  too 
scarce  to  supply  all  of  them. 

These  observations  merely  confirm  our  previous  statement  that  the 
number  of  weevils  in  the  fall  is  controlled  entirely  by  the  food  supply. 

One  of  the  principal  factors  in  cutting  off  the  food  supply  of  the 
boll  weevil  in  the  fall  is  the  cotton  leaf-worm  or  so-called  “army 
worm”  ( Alabama  argillacea  Hbn.).  Whereas  this  insect  was  formerly  j 
considered  to  be  the  great  scourge  of  the  cotton  planter,  it  may  now 
be  said  to  be  an  almost  positive  advantage  in  territory  affected  by  the 
boll  weevil,  as  its  injury  does  not  ordinarily  occur  until  after  the  crop 
has  been  made,  and  all  further  fruiting  would  be  prevented  by  the  boll  J 
weevil.  As  soon  as  the  leaf  worms  have  stript  the  cotton  of  foliage  I 
and  squares  the  weevils  either  die  or  leave  for  fields  where  the}’'  may  j 
obtain  food.  This  was  strikingly  shown  in  an  examination  of  four 

I 


HIBERNATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL. 


7 


plats  at  Smith  & Carson’s  plantation  on  September  14,  1904.  In  plats 

11-3,  where  the  leaf  worm  had  stript  the  plants  clean  of  foliage,  but 
. 8 weevils  were  found  to  100  stalks  and  but  40  per  cent  of  the  squares 
were  punctured.  On  plat  4,  immediately  adjoining  these  plats,  which 
had  not  been  so  seriously  injured  by  the  leaf  worm,  there  were  27  squares 
to  a plant,  148  weevils  to  100  stalks,  and  70  per  cent  of  the  squares  were 
punctured. 

Mr.  Teltschick  has  given  us  some  interesting  observations  upon  the 
leaf  worm,  as  follows: 

As  far  back  as  I can  remember — some  twenty-odd  years — the  people  here  ( Lavaca 
County)  had  to  fight  the  leaf  worm  every  year.  Arsenic,  Paris  green,  and  London 
purple  were  used  with  varying  success.  At  first  the  worms  made  their  appearance 
as  early  as  June  and  frequently  hatched  in  such  numbers  as  to  enable  them  to  sweep 
a field  clean  in  less  than  48  hours.  Gradually,  however,  this  wave  of  worms  sub- 
sided; that  is  to  say,  they  made  their  appearance  later  and  later  in  the  season,  and 
became  fewer  in  numbers,  until  finally  when  the  boll  weevil  made  its  first  appearance, 
their  coming  was  no  longer  viewed  with  alarm.  On  the  contrary  they  were  often 
welcomed  by  the  farmers,  inasmuch  as  they  cleared  away  the  thick  foliage  of  the 
cotton  plant,  thus  often  saving  a considerable  number  of  the  bolls  at  the  bottom, 
which  would  otherwise  have  rotted  for  the  want  of  light  and  air. 

At  the  time  of  the  weevils  coming  here  (seven  or  eight  years  ago)  the  worms  were 
no  longer  regarded  as  a menace  to  the  cotton  crop;  they  made  their  first  appearance 
then  either  late  in  August  or  early  in  September.  They  kept  this  up  practically 
until  in  1902  and  1903  they  failed  to  come  at  all.  This  year  (1904)  they  reappeared 
early  in  September  and  completely  stript  cotton  of  its  foliage.  The  second  destruc- 
tive brood  of  worms  is  just  now  (October  2,  1904)  hatched,  and  there  is  every  reason 
to  believe  that  they  will  keep  the  stalks  bare  until  frost  as  they  did  in  former  years. 
It  will  have  to  be  admitted  that  during  1902-3,  when  cotton  grew  and  formed 
squares  undisturbed  up  to  the  first  frost,  which  occurred  in  December  of  both  years, 
an  opportunity  was  given  the  weevil  to  go  into  hibernating  quarters  later  in  the 
season  and  in  greater  numbers  than  would  have  been  the  case  had  the  further 
growth  of  cotton  been  prevented  either  by  man’s  or  nature’s  means. 

Thus  the  leaf  worm  accomplishes  practically  the  same  result  as  is 
obtained  by  grazing  stalks  with  cattle  and  may  be  considered  a most 
valuable  ally. 

The  number  of  weevils  which  go  into  hibernation  may  of  course  be 
decreased  by  the  thoro  grazing  of  the  cotton  with  cattle  before  frost, 
or  by  cutting,  plowing  out,  and  burning  the  stalks.  It  is  safe  to  say 
that  by  a thoro  fall  clearing  of  the  ground  the  number  of  weevils 
entering  hibernation  can  be  decreased  at  least  75  per  cent.  Weevils 
in  all  stages  are  thus  immediately  destroyed,  and  if  the  land  is  cleared 
of  cotton  a month  before  the  normal  hibernation  period  the  weevils 
then  escaping  are  almost  certain  to  starve,  as  has  been  shown  in  Table 
I,  before  it  becomes  cold  enough  for  them  to  hibernate. 

Under  normal  conditions,  as  noted  in  Table  III,  column  3,  the  num- 
ber of  weevils  to  a stalk  at  the  time  of  hibernation  will  vary  from  1 
for  every  2 stalks  to  2 for  each  stalk  in  badly  infested  fields,  the  num- 
ber depending,  as  before  stated,  entirely  on  the  food  supply  and 


8 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


weather  conditions.  There  seems  to  be  no  reason  to  believe  that  any 
difference  will  be  found  in  the  number  of  weevils  in  infested  fields  in 
northern  Texas  as  compared  with  southern  Texas  except  as  it  may  be 
controlled  by  these  factors,  for  after  the  third  brood  becomes  matured 
the  number  of  weevils  depends  entirely  upon  these  conditions. 

DEVELOPMENT  OF  IMMATURE  STAGES  DURING  NORMAL  PERIOD  OF 

HIBERNATION. 

In  southern  Texas  during  an  open  dry  winter  larvae,  pupae,  and 
adult  weevils  may  frequently  be  found  in  the  injured  bolls  hanging 
upon  the  cotton  stalks.  In  feeding  upon  the  bolls  the  larvae  frequently 
eat  a hole  thru  the  septum  between  two  locks  and  form  a small  cavity 
just  under  the  inner  surface  of  the  lock.  These  feeding  cavities 
become  lined  by  the  dried  and  hardened  excrement,  so  that  when  a 
lock  is  broken  to  pieces  the  weevil  cells  may  be  separated  out  and  have 
quite  the  appearance  of  seeds.  It  is  within  such  cells  that  the  imma- 
ture stages  pass  the  winter  in  the  bolls.  Occasionally,  however,  the 
larvae  eat  into  the  seed,  so  that  immature  stages  may  be  found  actually 
within  the  seeds.  This  is  undoubtedly  not  the  usual  habit  and  there 
seems  to  be  practically  no  danger  of  disseminating  weevils  actually 
secreted  inside  of  the  seeds.  W e have  been  unable  to  make  a personal 
examination  of  these  conditions,  but  on  February  20, 1903,  Mr.  W . T. 
Allgood,  of  Devine,  Medina  County,  Tex.,  wrote  us  sending  some 
cotton  bolls  and  seed,  in  which  we  found  4 weevils  alive,  1 dead,  1 
newly  transformed,  1 in  a seed,  and  also  2 seeds  which  seemed  to  have 
been  eaten  out  by  weevil  larvae,  but  which  contained  only  larvae  which 
may  have  been  parasitic  upon  the  weevil.  The  4 live  weevils  were 
kept  in  a tube  in  our  laboratory  until  about  April  1,  when  they  die  , 

owing  to  the  unsuitable  conditions.  tux 

Several  of  the  infested  seeds  were  evidently  entered  before  the 
shell  was  fully  hardened  and  the  normal  development  of  the  seed  pre- 
vented, whereas  in  other  cases  the  weevils  were  in  seeds  fully  devel- 
oped. It  seems  quite  reasonable  that  the  larv*  should  bore  into  the 
seeds  during  the  early  winter,  for  as  the  cotton  matures  the  seeds* 
would  be  more  succulent.  However,  it  seems  exceedingly  improba- 
ble that  weevils  could  be  disseminated  by  being  carried  in  the  seed, 
for  they  occur  within  the  seed  only  on  unopened  bolls  which  hangt 
upon  the  plant,  and  very  rarely  would  cotton  in  which  weevils  had 
entered  the  seed  ever  be  ginned. 

Early  in  March  of  the  same  year  Mr.  Allgood  sent  the  writer  quite  i, 
quantity  of  bolls,  which  were  examined  March  12  with  the  following 
results:  Out  of  200  bolls  165  contained  no  weevils  in  any  stage,  alivi 
or  dead,  but  of  these,  20  per  cent  had  been  noticeably  injured  >y 
weevils.  Forty,  or  20  per  cent,  contained  weevils  alive  or  dead  nl 
some  stage.  In  these  40  bolls  there  were  40  live  and  11  dead  pup* 


HIBEKN ATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL. 


9 


30  live  and  40  dead  adults,  and  5 dead  larvae.  Many  of  these  weevils 
had  just  transformed  from  pupae  and  were  still  soft  and  light  brown. 
Some  transformed  after  being  received.  But  one  live  larva  was  found 
in  all  the  material  examined.  Mr.  Allgood  wrote  the  writer  that  these 
bolls  had  been  collected  from  stalks  in  a neighbor’s  field  in  which  there 
were  7,000  plants  to  the  acre,  that  each  plant  held  from  12  to  15  bolls, 
and  that  the  bolls  sent  in  were  picked  at  random  from  the  field.  Upon 
this  basis,  disregarding  the  live  pupa?  but  counting  the  30  weevils 
which  were  found  alive  as  having  survived  the  winter,  there  would 
have  been  10,500  weevils  per  acre  in  the  spring.  If  but  one-third  of 
these  survived  there  would  have  been  3,500  per  acre,  or  more  than 
have  ever  been  recorded  in  any  field  observations.  If,  as  seems  quite 
possible,  but  one-fifth  survived,  there  would  have  been  2,100  per  acre, 
which  is  approximately  the  number  which  survived  in  Lavaca  County 
under  the  favorable  weather  conditions  of  the  winter  of  1903-4.  Mr. 
Allgood  wrote  that  cattle  were  then  grazing  in  these  fields,  but  it 
is  doubtful  if  the  cattle  would  have  eaten  many  of  the  dry  hardened 
bolls.  In  another  lot  of  48  bolls  and  forms  sent  b}7  Mr.  Allgood  at 
the  same  time,  we  found  18  uninhabited  large  bolls,  15  forms,  and  15 
small  bolls.  These  contained  17  live  weevils,  4 live  pupse,  4 dead 
pupa3,  and  2 dead  larva;,  or  one  live  weevil  to  every  3 bolls  or  forms. 
These  weevils  were  confined  in  a wooden  box  in  the  laboratory  and 
were  still  alive  April  10,  but  later  died,  as  no  food  could  be  supplied 
them  at  that  time  under  temperature  conditions  such  that  they  would 
normally  have  emerged.  Doubtless  they  would  all  have  emerged 
early  in  April  at  Devine.  The  temperature  at  Pearsall,  the  nearest 
weather  station  to  Devine,  during  the  winter  was  as  follows:  Decem- 
ber, 1902,  mean  54°,  lowest  30°;  January,  1903,  mean  51.8°,  highest 
80°,  lowest  29°;  February,  1903,  mean  52.8°,  highest  77°,  lowest  23°; 
March,  1903,  mean  60.6°,  highest  82°,  lowest  38°. 

It  will  be  seen  that  there  were  but  few  days  during  the  winter  in 
which  the  temperature  was  below  freezing.  The  total  mean  tempera- 
ture for  these  four  months  at  Pearsall  was  but  63°  less  than  the  total 
normal  mean  for  southwestern  Texas  during  this  time,  and  the  rain- 
fall at  Pearsall  was  but  6.34  inches  greater  than  the  normal  for  south- 
western Texas,  no  normal  records  for  Pearsall  being  given.  The 
total  rainfall  of  these  months  is  normally  but  7.51  inches  for  southern 
Texas,  so  that  the  rainfall  was  nearly  double  the  normal  and  the 
winter  would  appear  to  have  been  exceedingly  unfavorable  for  the 
hibernation  of  weevils  in  their  usual  places  of  shelter.  However, 
weevils  which  developed  in  the  unopened  bolls  were  almost  entirely 
protected  from  the  excessive  rainfall,  and  the  temperature  being  nor- 
mal they  would  probably  survive,  while  those  weevils  which  went  into 
hibernation  in  all  usual  places  in  the  fall  would  doubtless  have  suffered 
an  excessive  mortality  due  to  the  unusual  rainfall. 


10 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


Immature  stages  and  adult  weevils  are  often  found  in  early  winter 
in  the  unopened  bolls  hanging  on  the  stalks  thruout  the  infested 
regions.  We  received  live  adult  weevils  in  bolls  from  Hamilton, 
Hamilton  County,  in  December,  1903,  and  they  have  been  observed 
here  and  elsewhere,  but  we  have  no  record  of  weevils  having  been 
found  alive  in  these  situations  in  early  spring  in  central  Texas,  and 
it  is  exceedingly  doubtful  if  many  of  them  would  survive  the  winter 
except  in  southern  Texas. 


Table  II.  — Condition  of  immature  stages  of  weevils  after  date  of  normal  hibernation. 


o 

h3. 

Date. 

1 Number  of  squares  or 
bolls  examined. 

1 

2 

3 

4 

1903. 
Nov.  13 
Nov.  12 
Nov.  18 
Nov.  20 

a 550 
a 98 
a 50 
a 200 

5 

Nov.  22 

a 100 

6 

Nov.  28 

a 100 

7 

Nov.  26 

a 200 

8 

Nov.  30 

1 o 200 

9 

Dec.  4 

« 200 

10 

....do  ... 

a 200 

11 

do ... 

a 200 

12 

Dec.  12 

Ja200 

\cl00 

13 

14 

15 

16 

Dec.  5 
....do... 
Dec.  4 
do  . . . 

a 250 
c 250 
a 500 
c 200 

Contain- 
ing eggs. 

Containing  larvse. 

H 1 

0) 

In 

Per  cent  of  squares  show- 
weevil  injury,  but  no 
stage  present. 

Per  cent  of  total. 

Per  cent  unhatched. 

Per  cent  of  total. 

Per  cent  less  than 
half  grown. 

Per  cent  over  half 
grown. 

Per  cent  alive. 

Per  cent  dead. 

Containing  pupae, 
cent  of  total. 

OG  0> 

!ga 

oj  a> 

C71— 

02 

O a> 

li 

o O 

<D  > 
CL|  > 

9. 15 

25.5 

0 

40.5 

25 

8 

24 

10 

14 

0 

io 

12 

2 

100 

9 

4 

100 

100 

4 

2 

100 

100 

1 

b 100 

& 100 

1 

b 99 

b 100 

b 100 

12.8 

100 

b 87. 2 

0 

42 

57 

43 

100 

0 

b 95. 8 

4 

100 

100 

0 

b 96 

Remarks. 


Collected  Nov.  7. 

Squares  frozen  Nov. 18. 

Collected  from  plant  Nov. 
15. 

Collected  from  ground 
Nov.  22. 

Collected  from  ground 
Nov.  8. 

One-half  collected  from 
ground,  one-half  from 
plant,  Nov.  1. 

One-half  collected  from 
ground,  one-half  from 
plant,  Nov.  15. 

One-half  collected  from 
ground,  one-half  from 
plant,  Nov.  18. 

One-half  collected  from 
ground,  one-half  from 
plant,  Nov.  22. 

One-half  collected  from 
ground,  one-half  from 
plant,  Nov.  24. 

One-half  collected  from 
ground,  one-half  from 
plant,  Nov.  28. 


a Squares. 

b Squares  with  no  stage  of  weevil  in  them.  Percentage  injured  unknown,  but  probably  40  per  cent 
as  in  lot  1. 
c Bolls 


In  November  and  December,  1903,  Mr.  Conradi  made  careful  obser- 
vations at  College  Station  upon  the  condition  of  the  immature  stages 
after  the  freeze  of  November  18.  The  results  of  these  observations 
are  shown  in  Table  II.  It  will  be  noticed  that  no  pupa?  or  adults 
were  found  in  over  3,600  squares  and  bolls  examined,  showing  that 
egg  laying  had  temporarily  ceased  during  some  period  before  Novem- 
ber 1.  The  most  probable  explanation  of  this  remarkable  absence  of 


HIBERNATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL. 


11 


pupse  and  adults  in  the  presence  of  eggs  and  larvae  is  that  an  outbreak 
of  the  cotton  leaf-worm  ( Alabairta  argillacea  Hbn.)  had  completely 
defoliated  the  plants  during  the  latter  part  of  September,  preventing 
entirely  the  formation  of  squares,  and  thus  stopping  abruptly  for  a 
short  time  the  multiplication  of  the  weevils  in  squares.  Subsequent^ 
squares  were  formed,  and  when  these  became  large  enough  the  repro- 
duction of  weevils  was  resumed  after  about  November  1,  so  that  most 
of  the  larvae  found  were  over  half  grown.  In  lots  4 and  5,  when  exam- 
ined November  20  and  22,  from  10  to  12  per  cent  of  the  eggs  were  still 
unhatched.  It  seems  probable  that  at  this  time  some  of  the  eggs,  but 
no  large  percentage,  failed  to  hatch.  Most  of  the  larvae  died  during 
the  first  stage  and  but  few  lived  to  be  over  half  grown.  On  Novem- 
ber 12,  in  lot  2,  25  eggs  were  found  in  98  squares,  which  were  col- 
lected November  7,  showing  that  the  egg  period  had  been  doubled. 
Mr.  Conradi  notes  in  this  connection  that  the  life-history  period  was 
first  noticed  to  be  decidedly  lengthened  after  November  9,  eggs  laid 
November  10  requiring  5 days  to  hatch.  From  24  eggs  hatched 
between  November  24  and  28,  15  larvae  died  within  a day  after  hatch- 
ing, 7 by  th£  time  they  were  half  grown,  and  but  2 developed  into 
weevils,  which  emerged  December  4. 

On  December  12  an  occasional  larva  was  found  in  the  field  and  sev- 
eral were  brought  into  the  laboratory,  where  3 transformed  to  pupee 
January  7,  but  then  died.  They  would  undoubtedly  have  failed  to 
pupate  in  the  field. 

MORTALITY  OF  HIBERNATING  WEEVILS. 

The  mortality  of  weevils  during  hibernation  is  shown  in  Tables  I and 
III.  Table  I gives4  the  mortality  of  weevils  confined  in  cages  at  dif- 
ferent dates  from  October  7 to  November  17,  as  previously  described. 
In  but  two  lots  did  weevils  survive  the  winter.  In  these  lots  (5  and  7), 
of  500  weevils  an  average  of  6.2  per  cent  survived  the  winter  and  were 
active  between  March  22  and  March  24.  On  March  21,  however,  10.5 
per  cent  were  alive,  and  it  was  noted  that  these  weevils  had  been  active 
since  March  18,  so  that  practically  7.5  per  cent  of  the  two  lots  survived 
the  winter  under  the  supposedly  favorable  conditions  furnished  them 
in  the  hibernation  cages. 

9223— No.  63,  pt  1—07 3 


12 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 
Table  III. — Percentage  of  weevils  surviving  hibernation  infields. 


Year. 

Locality. 

Number  of  weevils 
to  a stalk  in  fall.  | 

Weather:  December- 
March. 

Date  first 
emerged. 

Dates 

counted, 

inclusive. 

Weevils  counted. 

Area 

counted. 

Number  of  weevils 
to  100  stalks. 

Percentage  surviv- 
ing hibernation. 

Rainfall. 

Tempera- 

ture. 

Win- 

ter. 

Nor- 

mal. 

Win- 

ter. 

Nor- 

mal. 

1900-1 

Vienna  « 

ft +5. 54 

8. 32 

+ 2.7 

55.8 

Mar. 

10 

10  acres 

1902-3 

do 

1.5 

+ 6.80 

8.32 

+ .5 

55.8 

£ acre  c 

1903-4 

do 

(?) 

-6. 08 

8. 32 

+ 14.1 

55.8 

Mar. 

*i5* 

MaVi7d::: 

2*400 

1 acre 

31.0 

d 30 

1900 

Booth 

e-4-5.  71 

14.47 

-5.0 

55.5 

May  22-31. 

2,000 

2 acres 

13.0 

13 

1903 

Hunter 

/ +9.  60 

7.02 

- .8 

54.7 

May  30 

6 

140  stalks . . 

4.0 

1902 

Wellborn  . . 

(/— 8.  84 

13. 40 

-9.1 

55.7 

May  22-29. 

397 

2 acres 

2.5 

2.5 

1903 

do 

h2. 00  <7+2. 91 

13. 40 

-11.6 

55.7 

May 

"8* 

June  26- 

1 

2, 125 stalks. 

.04 

.08 

1 

July  17. 

1903-4 

do 

1.00 

{7-2.45 

13.40 

+ 2. 1 

55. 7 

Apr. 

17 

May  20- 

26 

1,600  stalks. 

1.6  . 

1.6 

June  17. 

1903 

College  Sta- 

-1.38 

12.72 

-3.5 

53.6 

May 

15 

June  18... 

5 

940  stalks . . 

.5  : 

tion.  i 

1903 

doA 

-1.38 

12.72 

- 3.5 

1 53.6 

do 

2 

40  stalks  . . . 

5.0 

5.0 

1904 

doJ 

".*75 

-6. 12 

12. 72 

+14.1 

53.6 

Mar. 

*29* 

May  19- 

49 

2,930  stalks. 

1.66 

1.66 

Junel4. 

1904 

do.»* ... 

1.00 

- 6.12 

12.  72 

+14.1 

53.6 

Apr. 

1 

May  22- 

20 

1,840  stalks. 

1.0 

1.0’ 

June  9. 

1904 

Rosprim.M.. 

(?) 

-6.12 

12.72 

+14.1 

53.6 

Apr. 

8 

June  7 

10 

1,000  stalks. 

1.0 

a Observations  by  Louis  Teltschick. 
ft  Record  for  Hallettsville. 
c Three-fourths-acre  trap  rows. 
d Estimate  of  several  fields,  May  17. 
e Records  of  Houston,  as  far  as  given. 
/Record  for  New  Braunfels. 
a Records  for  Brenham. 


h August  17,  2 weevils  pei;100  stalks. 
i In  sorghum  in  1902. 
fc  Cotton,  1902,  a crossroad  by  barn. 
l Cotton  not  destroyed  in  fall  of  1903. 

Cotton  destroyed  in  fall  of  1903. 
n In  corn  in  1903. 


In  the  field  we  have  never  found  the  percentage  surviving  at  the 
college  to  approach  this  number,  except  in  one  instance.  As  shown 
in  Table  III,  in  the  spring  of  1903  cotton  was  planted  near  the  college 
barn,  where  it  had  been  grown  the  previous  year  and  left  standing. 
The  weevils  had  the  most  favorable  conditions  possible  for  hibernat- 
ing around  the  barn.  They  appeared  so  numerously  on  the  cotton  in 
the  following  spring  that  on  June  18  there  were  5 hibernated  weevils 
to  every  100  stalks.  More  weevils  were  found  in  this  cotton  thruout 
the  year  than  in  any  other  locality.  If  it  be  fair  to  assume  that  about 
one  weevil  to  a stalk  occurred  in  this  field  at  the  time  of  hibernation 
in  the  fall  of  1902,  then  about  5 per  cent  survived.  It  is  quite  possi- 
ble that  there  were  more  than  this  number  in  the  fall,  and  the  per- 
centage surviving  would  therefore  be  somewhat  less.  Elsewhere,  in 
the  neighborhood  of  the  college,  not  over  2 per  cent  have  ever  been 
found  to  survive  the  winter  in  the  field,  tho  several  fields  within  a 
distance  of  4 miles  have  been  carefully  observed. 

In  the  Brazos  bottom,  on  Smith  & Carson’s  plantation,  Professor 
Mally  (report,0  p.  16)  records  picking  397  weevils  from  2 acres  May 
22-29,  1902,  or  2.5  weevils  to  100  stalks,  which  would  give  not  over  2.5 
per  cent  surviving  hibernation.  In  1903  but  1 weevil  was  found  to 
2,125  stalks,  or  0.04  to  100  stalks,  which  would  give  a percentage  of 
hibernation  of  not  over  0.04  and  probably  0.08,  as  there  were  2 weevils 


Report  on  the  Boll  Weevil,  Austin,  Tex.,  August,  1902. 


HIBERNATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL. 


13 


to  a stalk  the  previous  fall.  During  the  present  year  (1904)  but  1.6  per 
cent  survived  hibernation  on  the  plots  counted.  This  figure  is  open  to 
slight  error,  as  upon  this  plantation  there  were  possibly  20  acres  of 
cotton  about  a mile  away,  which  were  planted  much  earlier  than  was 
most  of  the  plantation.  This  early  cotton  was  infested  at  the  rate  of  20 
weevils  to  100  stalks  on  May  31.  It  is  evident  that  the  weevils  which 
hibernated  on  the  plantation  as  a whole  had  concentrated  on  this  early 
planting,  but  if  the  total  number  of  weevils  upon  this  early  cotton  had 
been  distributed  over  the  whole  acreage  there  would  have  been  not 
over  2-J-  weevils  per  100  stalks  or  2.5  per  cent  surviving  hibernation 
at  the  most.  Two  per  cent  would  probably  be  very  nearly  correct. 
At  Victoria,  Hunter  and  Hinds  have  shown  that  approximately  15  per 


Fig.  3. — Rainfall  and  temperature  records  of  College  Station  and  Victoria,  Tex.,  for  1902-3,  compared 

with  normals. 


cent  of  late-developed  weevils  survived  the  winter  of  1902-3  in  hiber- 
nation cages.  The  very  careful  records  made  by  Mr.  Teltschick  by 
hand-picking  the  weevils  during  the  spring  (see  p.  59  of  that  report) 
shows  that  this  very  closely  approximates  the  number  of  weevils  nor- 
mall}7  surviving  under  field  conditions  in  Lavaca  County,  but  that  dur- 
ing the  last  winter  (1903-4)  fully  30  per  cent  of  the  weevils,  or  twice  as 
many  as  usual,  hibernated  successfully.  In  1900  Professor  Mally’s 
records  (1.  c.,  p.  32)  show  that  Mr.  Kramer  picked  2,000  weevils  at 
Booth,  Fort  Bend  County,  or  13  to  100  stalks,  which  would  give  at 
least  13  per  cent  surviving  the  winter,  in  a latitude  practically  the 
same  as  that  of  Vienna.  It  will  be  seen,  therefore,  that  whereas  15 
per  cent  may  be  considered  an  average  of  the  number  surviving 


14 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


hibernation  in  southern  Texas,  normally  onty  about  2 per  cent,  and 
never  over  5 per  cent,  survive  under  held  conditions  at  College  Station, 
and  about  2£  per  cent  in  the  Brazos  bottom  at  Wellborn.  In  other 
words,  only  about  one-fifth  as  many  weevils  survive  the  winter  here  as 
do  in  southern  Texas.  Whether  a corresponding  difference  will  be 
found  in  the  mortality  between  central  Texas  and  northern  Texas 
remains  to  be  determined.  This  will  depend  on  the  weather  condi- 
tions discust  below,  but  it  seems  doubtful  that  there  will  be  so  great 
a difference. 

TIME  OF  GREATEST  MORTALITY  DURING  HIBERNATION. 

In  Table  I it  may  be  seen  that  in  lots  4,  5,  and  6,  including  600 
weevils,  there  was  a mortality  of  at  least  51  per  cent  during  the  month 
of  December,  and  that  in  lot  5 there  was  a mortality  of  9.6  per  cent 
during  January  and  but  2.8  per  cent  during  the  remainder  of  the 
year.  Referring  to  figure  2 it  may  be  seen  that  at  College- Station  in 
the  winter  of  1903-4  the  rainfall  was  greatest  in  December,  while 
during  the  balance  of  the  winter  it  was  below  normal.  The  maximum 
in  December  approached  the  normal,  whereas  usually  the  maximum 
for  winter  occurs  in  January.  The  temperature  was  very  close  to 
normal  thru  January,  but  considerably  above  normal  during  the 
remainder  of  the  winter. 

In  general,  an  excessive  rainfall  seems  to  be  a most  important  factor 
in  increasing  the  mortality  of  the  weevil.  The  temperature  does  not 
usually  depart  sufficiently  from  the  normal  to  be  an  important  factor, 
except  that  when  occurring  with  a deficient  rainfall  an  excess  of  tem- 
perature appears  to  be  decidedly  beneficial  to  hibernation.  By  refer- 
ring to  figures  4 and  5,  showing  the  normal  rainfall  and  temperature  for 
Hallettsville,  Tex.,  and  the  monthly  mean  temperature  and  rainfall  dur- 
ing the  winters  of  1899-1900, 1900-1901, 1902-3,  and  1903-4,  it  may  be 
seen  that  in  1900-1901  there  was  a decided  deficiency  in  rainfall  and  a 
slight  excess  in  temperature,  whereas  in  1902-3  there  was  an  abnor- 
mally large  rainfall  and  a nearly  normal  temperature.  In  1901  and 
1904  the  weevils  survived  in  unusally  large  numbers,  while  in  1903 
the  number  hibernating  successfully  was  considerably  less  than  nor- 
mal. The  same  general  conclusions  are  shown  when  the  rainfall  and 
temperature  records  as  given  for  College  and  Brenham  in  Table  III 
are  compared  with  the  percentage  of  weevils  surviving  at  College  and 
in  the  Brazos  bottom  below  Wellborn.  The  rainfall  and  temperature 
records  are  shown  diagrammatically  in  figures  2 and  3,  giving  also 
the  normal  rainfall  and  departure  from  normal  for  College  Station 
and  Victoria  in  1902-3  and  1903-4. 

If  it  be  true  that  the  rainfall  is  the  most  important  climatic  factor 
in  the  mortality  of  the  hibernating  weevils,  it  is  interesting  to  com- 
pare the  rainfall  of  different  sections  of  the  State  as  given  by  the 


HIBERNATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL. 


15 


Fig.  4.— Rainfall  and  temperature  records,  Hallettsville,  Tex.,  1899-1901,  compared  with  normals  for 

each  year. 


16 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


Flo.  6.— Rainfall  and  temperature  records,  Hallettsville,  Tex.,  1902-1904,  compared  with  normals  for 

each  year. 


HIBERNATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL. 


17 


Texas  section  of  the  U.  S.  Weather  Bureau.  The  normal  total  rain- 
fall during*  the  winter  months  of  December  to  March  for  southwestern 
Texas  is  6.46  inches,  for  the  coast  country  8.26  inches,  and  for  central 
Texas  9.83  inches,  while  the  total  normal  effective  winter  tempera- 
ture a during  December  to  March,  inclusive,  is,  for  southwestern  Texas 
1,631.4°  F.,  for  the  coast  country  1,190.6°  F.,  for  eastern  Texas 
1,483.1°  F.,  for  northeastern  Texas  934.9°  F.,  and  for  central  Texas 
1,294.3°  F.  The  average  effective  temperature  for  the  eastern  and 
southwestern  countries  is  therefore  from  200°  to  300°  higher  than  that 
of  central  Texas  for  this  period  and  from  450°  to  700°  F.  higher  than 
that  of  the  coast  and  northeastern  Texas.  If  we  consider  the  more  crit- 
ical period  of  December  to  February,  inclusive,  the  southwestern  and 
eastern  countries  have  300°  to  200°  F.  more  effective  temperature 
than  central  Texas  and  from  600°  to  500°  F.  more  than  northeastern 
Texas.  It  would  therefore  seem  that  both  the  temperature  and  rain- 
fall are  far  more  favorable  to  the  successful  hibernation  of  the  weevil 
in  southwestern  Texas  than  in  central,  coast,  or  northeastern  Texas,  and 
that  the  conditions  as  to  temperature  and  rainfall  in  the  coast  country 
during  the  critical  period  are  very  similar.  In  northeastern  Texas, 
however,  as  the  weevils  do  not  emerge  from  hibernation  until  con- 
siderably later  in  the  spring,  the  larger  rainfall  occurring  during  April 
may  have  some  effect  on  them. 

As  before  mentioned,  floods  during  the  period  of  hibernation  seem 
to  have  a marked  effect  upon  the  mortality  of  the  weevil,  as  there 
were  notably  fewer  weevils  thruout  the  Brazos  bottom  in  this  section 
in  the  spring  following  the  flood  of  February,  1903. 

PLACES  OF  HIBERNATION. 

Considerable  time  has  been  spent  in  attempting  to  find  the  places  in 
which  the  weevils  spend  the  winter,  but  the  results  have  been  rather 
unsatisfactory.  This  has  also  been  the  experience  of  many  observing 
practical  farmers.  Numerous  cotton  fields  were  examined  in  the 
neighborhood  of  the  college  during  January  and  February,  1903,  and 
tho  Mr.  Newell  and  the  writer  made  diligent  search  in  all  conceivable 
places  over  a considerable  acreage,  embracing  an  area  of  2 miles,  ex- 
amining cornstalks,  grass,  bark,  fence  posts,  gins,  etc.,  we  found  but 
1 live  boll  weevil  during  the  winter  and  this  one  was  under  a small 
pile  of  dried  manure.  On  -November  29,  1903,  Mr.  A.  F.  Conradi 
found  2 weevils  in  a pile  of  old  cotton  brush  in  our  experimental  field, 
3 under  the  bark  of  a log  near  the  field,  and  2 in  the  cotton  field  under 
a bunch  of  dead  cotton  leaves.  On  December  15  a thoro  examination 

a Total  normal  effective  temperature  is  reckoned  for  each  month  by  subtracting  43° 
F.  (the  point  at  which  animal  activity  is  supposed  to  begin)  from  the  normal  mean 
temperature  for  that  month,  multiplying  the  difference  by  the  number  of  days  in 
that  month,  and  adding  together  the  four  products  thus  obtained. 


18 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


was  made  of  logs,  leaf  rubbish,  etc.,  in  a ravine  adjoining  our  cotton 
field,  but  no  weevils  were  found.  On  December  28  a similarly  futile 
search  was  made  along  Carters  Creek,  in  which  neighborhood  a good 
deal  of  cotton  had  been  grown.  On  January  5,  1904,  a 30-acre  cotton 
field  was  thoroly  examined,  but  no  weevils  were  found.  Corn  stubble 
standing  near  a very  badly  infested  field  was  also  examined  without 
finding  any  weevils.  Our  information  regarding  the  hibernating 
places  of  the  weevil  is  therefore  more  of  a deduction  based  upon  obser- 
vations of  the  places  in  which  they  appear  first  in  the  spring  than  a 
conclusion  from  actual  observations.  The  observations  by  Mr.  Con- 
radi  in  the  early  winter  probably  indicate  the  normal  places  for  hiber- 
nation— that  is,  under  dead  leaves,  in  old  cotton  brush,  and  under 
loose  bark.  In  the  hibernation  cages,  where  the  weevils  were  furnished 
an  abundance  of  rubbish,  it  was  found  that  many  of  them  which  were 
hibernating  successfully  had  crawled  into  the  cavities  made  by  borers 
in  dead  wood  and  in  similar  positions  where  they  were  well  protected. 
It  has  been  often  noticed  that  in  a wooded  country  the  weevils  appear 
first  in  spring  along  the  borders  of  fields  next  to  the  woods  and  gradu- 
ally work  inward  from  the  edges,  so  that  it  seems  probable  that  in  a 
wooded  country  most  of  them  hibernate  in  woodland.  Around  out- 
buildings and  barns  also  are  found  favorable  places,  as  there  is  always 
more  or  less  rubbish  and  protection  in  such  situations.  In  1903  more 
than  five  times  as  many  weevils  were  found  in  a piece  of  cotton  near 
the  college  barn,  where  cotton  had  been  grown  the  previous  year,  than 
were  found  in  any  other  locality  in  that  neighborhood.  It  is  also 
noticeable  that  weevils  are  always  more  numerous  near  gins  than  at  a 
distance  from  them.  Undoubtedly,  where  much  rubbish  and  grass  are 
present  and  where  the  soil  remains  loose  and  is  not  packed  by  rains, 
large  numbers  of  the  weevils  winter  in  the  cotton  fields.  The  fact 
that  in  1903  an  exceedingly  small  number  of  weevils  survived  on 
Smith  & Carson’s  plantation  on  the  Brazos  River  must  have  been  due 
to  their  having  hibernated  in  the  field,  large  numbers  having  been 
killed  otf  by  the  excessive  rains  and  doubtless  more  by  the  flood  of 
February,  1903,  which  covered  the  fields  to  a depth  of  several  inches 
over  a large  part  of  the  plantation.  It  was  quite  noticeable  that  few 
weevils  were  found  on  Brazos  bottom  plantations  in  this  section  in 

1903.  In  all  probability  the  flood  would  have  had  but  little  effect  later 
in  the  season  after  the  weevils  had  emerged. 

It  is  noticeable  that  weevils  are  much  more  abundant  where  cotton 
is  planted  in  fields  where  sorghum  stubble  has  been  allowed  to  remain 
all  winter  adjoining  a last  year’s  cotton  field.  Thus,  in  the  spring  of 

1904,  the  first  weevils  found  on  Smith  & Carson’s  plantation  were  on  a 
cut  of  cotton  along  the  Brazos  River  which  had  been  in  sorghum  and 
surrounded  by  cotton  in  1902  and  where  several  large  sorghum  stacks 
stood  thru  the  winter.  Tho  planted  early  and  kept  well  cultivated, 


HIBERNATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL. 


19 


so  little  cotton  was  made  on  this  piece  that  it  was  not  worth  picking, 
while  cotton  planted  at  the  same  time  and  cultivated  in  the  same  man- 
ner on  other  parts  of  the  plantation  made  a good  yield. 

Professor  Mally  (1.  c.,  p.  57)  has  given  the  observations  of  Mr. 
Teltschick  upon  finding  weevils  hibernating  in  the  crevices  of  the  soil 
around  the  cotton  stalks  and  roots,  at  a depth  of  3 inches.  On  March 
7,  1901,  a raw,  windy  day,  upon  35  stalks,  he  found  7 live  and  2 dead 
weevils  from  1 to  3 inches  below  the  surface.  In  September,  1902, 
he  stated  that  he  had  again  found  weevils  in  a similar  situation  during 
the  previous  spring,  but  not  as  many  of  them  as  in  1901.  Mr.  Telt- 
schick recently  writes  as  follows: 

I found  but  few  weevils  in  crevices  around  stalks  during  the  last  two  winters, 
partly  because  there  were  no  crevices  (frequent  rains  filling  them  up  as  soon  as 
formed)  and  partly  because  freezes  were  severe  enough  to  keep  cotton  from  coming 
out  during  any  part  of  the  last  two  winters;  whereas  in  1900  we  had  neither  rain 
enough  to  till  up  crevices  nor  frost  enough  to  keep  cotton  from  budding  out  at  inter- 
vals at  the  base  of  the  stalk,  which  latter  fact  accounts,  no  doubt,  for  the  relatively 
large  number  of  weevils  found  within  the  crevices. 

TIME  OF  EMERGENCE  FROM  HIBERNATION. 

Hunter  and  Hinds a state  that  the  first  weevils  emerge  when  the 
mean  average  temperature  has  been  for  some  time  above  60°.  Our 
observations  at  the  college  upon  the  earliest  emergence  from  hiberna- 
tion are  as  follows:  In  1903  the  first  weevil  was  found  on  May  15  at 
the  college  after  carefully  searching  about  100  feet  of  unchopped 
row.  Repeated  examinations  during  the  next  two  weeks  showed  but 
a very  small  number  of  weevils.  On  May  8 a weevil  was  found  in 
the  Brazos  bottom  after  hunting  about  20  minutes,  and  after  May 
5 planters  in  the  bottom  occasionally  reported  finding  weevils.  In 
1904,  on  cotton  planted  March  17,  the  first  weevils  were  found, on 
March  29.  On  April  17  and  18  only  an  occasional  weevil  could  be 
found  at  College  Station  or  in  the  Brazos  bottom  after  a considerable 
search.  In  1903  Mr.  Teltschick  wrote  me  on  March  1 from  Lavaca 
County  as  follows: 

Up  to  a severe  freeze  of  two  weeks  ago  (February  16-17)  I could  at  any  time  find 
some — not  many — in  my  neighbors’  fields  apparently  feeding  on  buds  or  small  leaves 
at  the  base  of  the  stalk,  which  had  never  been  entirely  frozen. 

However,  he  did  not  find  many  on  his  own  cotton  until  April,  when 
he  picked  some  from  trap  rows  which  were  planted  on  March  13. 
In  1904  he  noticed  the  first  weevils  about  the  middle  of  March,  but,  as 
in  previous  years  in  other  localities  in  southern  Texas,  we  have  records 
of  their  feeding  on  shoots  from  stumpage  cotton  much  earlier  than 
this.  In  general,  it  seems  that  when  the  normal  mean  temperature 


«Bul.  45,  Div.  Ent.,  U.  S.  Dept.  Agric.,  p.  82. 


20 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


passes  68°  F.  the  first  weevils  commence  to  emerge  from  hibernation, 
and  this  conclusion  is  confirmed  by  all  of  our  observations. 

It  will  be  seen  from  the  temperature  curves  in  figure  2 that  at 
Victoria  the  normal  mean  temperature  usually  reaches  68°  about  April 
1 and  at  College  about  April  15.  Figure  2 shows  that  in  1903  the  mean 
average  temperature  reached  68  about  one  week  later  at  Victoria. 
In  1904  (fig.  2)  the  mean  temperature  reached  68°  about  March  10  at 
Victoria  and  the  first  weevils  were  found  about  the  middle  of  March,  I 
which  is  also  true  of  Lavaca  County,  while  at  College  Station  68°  was 
reached  a week  later  than  usual,  but  the  tamperature  was  above  66° 
for  the  month  preceding  April  15.  If  the  mean  rise  in  temperature  ; 
from  February  15  to  May  15  be  plotted,  the  line  would  reach  68° 
about  April  5,  which  very  closely  approximates  the  date  of  the  first 


Fig.  6. — Comparison  of  normal  temperatures,  October  15  to  June  15,  for  various  districts'in  Texas. 


appearance  of  the  weevils  at  College  Station  for  that  year.  From  all 
the  data  available,  therefore,  it  seems  very  safe  to  assert  that  when 
the  temperature  reaches  68°  or  has  been  above  65°  for  several  weeks  i 
the  first  weevils  will  emerge.  By  consulting  figure  6 this  time  nmj'  ; 
be  seen  for  any  section  of  the  State.  The  curve  shows  that  weevils  l 
would  normally  emerge  from  hibernation  about  10  da\rs  earlier  in  the  I 
southwestern  and  coast  countries  than  in  central  and  northeastern  Texas,  i 
and  about  20  days  earlier  than  in  northwestern  or  western  Texas. 

The  greatest  number  of  weevils  emerge  considerably  later  and  usu-  I 
ally  about  the  time  cotton  commences  to  square.  The  time  of  the 
principal  emergence  and  the  beginning  of  general  oviposition  by  the 
hibernating  brood  is  practically  the  same.  A few  belated  weevils 
appear  after  this  time,  as  is  shown  by  the  field  records  of  Mr.  Telt-I 
schick  for  1903  and  1904.  For  if  the  bulk  of  the  weevils  emerges  at  the 


HIBERNATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL. 


21 


time  the  cotton  commences  to  square  freely  and  frequent  counts  be 
made,  the  number  will  be  found  to  decrease  for  a few  days,  and  there 
is  then  a sudden  rise  due  to  the  maturing  of  the  first  brood  early  in 
June,  and  it  is  practically  impossible  to  determine  in  the  field  whether 
any  hibernated  weevils  subsequently  emerge.  However,  in  1904,  it  is 
certain  that  no  weevils  emerged  later  than  June  29,  for  at  that  date 
practically  no  weevils  could  be  found  in  the  field,  tho  the  bulk  of  the 
hibernating  weevils  appeared  from  June  5 to  June  10.  Consequently 
this  year  (1904)  certainly  no  weevils  emerged  later  than  22  days  after 
the  maximum  number. 

It  has  previously  been  shown  by  Professor  Mally  (1.  c.,  p.  16)  and 
by  Hunter  and  Hinds,  and  noted  above,  that  the  weevils  emerge  grad- 
ually over  a period  of  from  4 to  6 weeks,  normally  more  nearty  the 
latter  time.  This  range  covers  practically  the  same  length  of  time  as 
from  planting  to  the  formation  of  the  first  squares  on  the  bulk  of  the 
cotton  in  any  given  community.  The  gradual  emergence  from  hiber- 
nation is  shown  by  the  number  of  weevils  to  100  stalks  in  Table  III 
for  1904  at  College  Station.  In  1903  Mr.  Teltschick  picked  the  wee- 
vils from  three-fourths  of  an  acre  of  trap  rows,  planted  March  13,  on 
which  the  first  bloom  appeared  May  28,  and  secured  weevils  as  follows: 

April,  about  40  weevils. 

May  4,  36  weevils  picked  in  1 hour’s  time. 

May  11,  43  weevils  picked  in  1 hour’s  time. 

May  18,  68  weevils  picked  in  2 hours’  time. 

May  25,  54  weevils  picked  in  4 hours’  time. 

In  1904  Mr.  Teltschick  made  observations  especially  to  determine 
this  point.  His  notes  are  as  follows: 

Two  plats  of  one-fourth  of  an  acre  each  wTere  selected  in  that  part  of  the  field 
which  was  farthest  away  from  my  own  as  also  from  any  other  cotton  patch.  The 
two  plats  themselves  were  separated  by  25  rows  of  corn  and  surrounded  by  sugar 
cane  on  two  sides  and  by  timbered  land  on  the  other  two.  No  cotton  had  been 
grown  on  or  near  these  plats  in  3 years.  Plat  1 was  planted  in  King  cotton  March 
4,  wras  up  to  a good  stand  March  14,  and  chopped  to  a stand  April  11.  From  plat  1 
the  weevils  were  picked  as  follows: 

April  1,  14  weevils.  May  2,  96  weevils. 

April  11,  27  weevils.  May  12,  140  weevils. 

April  21,  26  weevils.  May  23,  150  weevils. a 

Plat  2 was  planted  in  Shine  cotton  April  25  (7  weeks  later  than  plat  1),  was  up  to 
a good  stand  April  30,  and  was  chopped  to  a stand  May  12  (one  month  later  than 
plat  1 ).  On  plat  1 the  first  squares  appeared  May  2 and  on  plat  2 May  28.  All  fallen 
and  flared  squares  were  picked  up  on  both  plats  at  intervals  of  8 days  up  to  July  1. 
From  plat  2 there  were  picked,  on  May  12,  3 weevils;  May  23,  35  weevils. 

These  records  show  very  clearly  the  gradual  emergence  of  the  wee- 
vils from  winter  quarters.  In  1903  the  maximum  number  of  weevils 

^Weevils  were  picked  also  during  June,  but  these  doubtless  belonged  to  the  first 

summer  brood. 


22 


PAPERS  ON  THE  COTTON  ROLL  WEEVIL,  ETC. 


appeared  on  May  18,  in  1904  on  Ma}^  23,  and  in  1901  on  Ma}7  10-15; 
but  as  the  intervals  between  pickings  were  a week  or  10  days  it  would 
seem  safe  to  judge  that  the  normal  time  for  the  maximum  number  to 
emerge  at  Vienna  is  about  May  15  to  20.  It  will  also  be  noticed  that 
the  weevils  appear  much  more  rapidly  and  early  on  early  planted 
cotton,  but  the  maximum  number  does  not  appear  at  the  time  of 
squaring  of  the  earliest  planted  cotton,  but  at  about  the  time  of  squar- 
ing of  the  main  crop,  thus  giving  a decided  advantage  to  the  early 
planted  cotton.  The  determination  of  the  exact  time  of  the  emergence 
of  the  maximum  number  of  weevils  will  be  practically  the  same  as 
that  for  the  time  of  maximum  oviposition  for  the  hibernating  brood, 
concerning  which  see  page  25,  and  which  in  Lavaca  County  will  ror 
mally  occur  about  May  20,  at  College  Station  about  June  1,  and  in 
northern  Texas  probably  about  June  10. 

PREVENTION  OF  HIBERNATION. 

It  may  be  readily  seen  from  the  foregoing  discussion  that  any 
methods  which  will  reduce  the  number  of  weevils  going  into  hiberna- 
tion in  the  fall  are  of  the  utmost  importance  in  the  control  of  the 
pest,  inasmuch  as  nature  aids  in  further  reducing  their  numbers  dur- 
ing the  winter.  All  students  of  the  problem  of  boll-weevil  control 
have  agreed  that  in  this  prevention  of  successful  hibernation  lies  the 
most  effectual  means  of  reducing  the  numbers  of  the  weevil  and  pre- 
venting injury  the  next  season.  Two  methods  are  advocated:  (1)  The 
destruction  of  the  stalks  in  the  fall  as  long  before  frost  as  possible, 
and  (2)  rotation  of  the  cotton  crop,  planting  on  land  not  in  cotton  the 
previous  year  and  as  far  from  such  land  as  is  possible. 

FALL  DESTRUCTION  OF  STALKS. 

By  the  destruction  of  the  stalks  as  early  as  possible  in  the  fall  the 
number  of  weevils  entering  hibernation  is  reduced  in  several  wa37s:| 
(1)  All  immature  stages  in  the  squares  and  bolls,  which  might  develop 
into  weevils  if  the  stalks  remained  standing,  will  be  destined.  (2)1 
Probably  three-fourths  of  the  adult  weevils  in  the  field  at  the  time  of 
burning  may  be  destroyed  if  the  work  be  properly  managed.  (3)  By  I 
clearing  the  field  of  cotton  some  time  before  the  normal  time  when 
weevils  will  enter  hibernation  their  food  is  destroyed  and  the  adults! 
either  starve  or  migrate  to  other  fields.  Were  this  work  done  uni-jti 
formly  over  a considerable  area,  the  weevils  would  surely  starve,: 
as  they  can  not  be  forced  into  hibernation  before  the  normal  time. 
That  a large  mortality  follows  if  this  is  attempted  is  shown  in  our 
records  (see  pages  2-3).  These  advantages  are  apparent,  tho  but  few 
actual  records  of  the  benefit  of  such  fall  destruction  of  stalks  have 
been  published.  From  the  conditions  under  which  experiments  must 
be  made  it  is  difficult  to  demonstrate  in  a tangible  way  the  actual 


HIBERNATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL. 


23 


benefit  to  be  thus  derived,  but  in  the  case  of  plats  burned  over  in  the 
fall  of  1903  we  found  there  were  far  fewer  weevils  in  1904  than  in 
fields  where  the  stalks  had  been  left. 

On  October  23  and  25  the  stalks  on  our  experimental  plats,  covering 
about  30  acres,  were  cut  with  a single  cutter  made  of  a V-shaped  sled, 
with  knives  projecting  out  and  backward  on  either  side  about  a foot 
beyond  the  rows.  A team  draws  the  cutter  with  a man  on  it,  cutting 
.2  rows  at  once  and  about  15  acres  per  day.  The  stalks  .were  then 
raked  and  piled,  and  were  dry  enough  to  burn  in  a week.  On  one- 
half  the  field  2 rows  in  every  20  were  left  standing  as  trap  rows.  No 
weevils  were  found  later  on  the  dried  piles,  but  they  had  assembled  in 
large  numbers  on  the  standing  trap  rows.  Thirty-six  were  found  on 
four  plants.  These  trap  row's  were  then  cut,  left  over  night  on  the 
ground,  raked  the  next  morning,  and  placed  on  the  dried  piles.  That 
afternoon  examination  by  the  writer  showed  that  on  the  green  stalks 
on  the  dried  piles  there  was  an  average  of  1 weevil  to  every  square 
and  boll,  often  5 or  6 being  found  on  a square.  The  torch  was  then 
applied  and  the  piles  quickly  burned.  After  this  many  weevils  were 
found  on  the  shoots  growing  out  from  the  stumpage  and  an  occasional 
stalk  that  was  left.  (This  might  be  obviated  more  completely  by 
plowing  out  the  stalks.)  A herd  of  cattle  was  therefore  turned  into 
the  field  and  all  herbage  was  devoured  in  a very  few  days.  A better 
destruction  could  hardly  be  desired,  and  but  little  extra  labor  and 
expense  was  involved. 

At  the  apiary  a small  plat  containing  two-thirds  of  an  acre  was  left 
with  the  stalks  standing  all  winter.  This  plat  was  surrounded  by  a 
grove  and  was  half  a mile  from  other  cotton. 

Observations  by  the  writer  show  that  in  1904  upon  the  30  acres 
upon  which  the  stalks  were  burned  there  appeared  of  the  hibernated 
brood  during  the  spring  but  1.2  weevils  to  100  stalks,  while  on  the 
apiaiy  plat  where  the  stalks  had  been  left  there  were  about  4 weevils 
to  100  stalks,  or  over  three  times  as  many  hibernated  successfully 
where  stalks  remained  standing  as  where  they  were  destroyed. 

Again,  on  July  13  the  field  where  stalks  were  burned  averaged  3.3 
weevils  to  100  stalks,  while  fields  of  Messrs.  Boyett  and  Gray,  just 
over  the  railroad,  not  100  yards  distant,  where  the  stalks  had  not  been 
burned,  tho  other  conditions  were  practically  similar,  had  6 and  12 
weevils  to  100  stalks,  respectively,  or  an  average  of  three  times  as 
many  weevils  as  on  the  field  where  stalks  were  burned. 

Were  all  conditions  exactly  the  same,  as  regards  culture,  land,  etc., 
and  were  it  possible  to  prevent  the  migration  of  the  weevils  from 
neighboring  fields  to  those  where  the  stalks  had  been  burned,  the  lat- 
ter would  undoubted^  show  a much  greater  yield  at  the  end  of  the 
season,  but  as  it  is  very  rarely  possible  to  eliminate  these  factors  the 


24 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


above  records  show  in  a striking  way,  based  upon  extensive  counts, 
the  difference  in  amount  of  infestation  during  early  summer  where 
stalks  have  been  destroyed  the  previous  fall. 


CROP  ROTATION. 

The  value  of  the  rotation  of  crops  was  strikingly  shown  by  the  dif- 
ference between  the  number  of  weevils  occurring  on  the  experiment 
station  variety  plats  at  the  college  barn,  where  cotton  had  been  planted 
the  previous  year  (1902),  with  corn  adjoining,  and  our  plats,  situated 
a mile  distant  on  land  which  had  never  been  in  cotton,  having  grown 
sorghum  in  1902,  tho  cotton  was  grown  not  100  yards  distant.  The 
cotton  was  planted  April  5 at  the  college  barn,  and  on  June  17  there 
were  5 weevils  to  100  stalks,  2 being  found  on  the  40  stalks  examined, 
whereas  on  the  other  field  there  were  but  0.5  to  100  stalks,  only  5 
being  found  on  940  stalks  examined.  Again,  on  August  13  the  varie- 
ties at  the  barn,  planted  May  3,  had  233  weevils  to  100  stalks,  163 
being  found  on  70  stalks,  while  only  5.5  to  100  stalks  occurred  in  the 
field  where  there  had  been  no  cotton  the  previous  year,  only  10  being 
found  on  180  stalks  from  all  parts  of  the  field.  On  the  same  day  48 
weevils  to  100  stalks  were  found  on  Mr.  James  Boyett’s  cotton,  just 
across  the  railroad  from  our  field,  his  land  having  been  in  cotton  the 
previous  year,  while  on  Mr.  Suber’s  cotton,  a mile  distant,  53  to  60 
per  100  stalks  were  found,  this  crop  also  following  cotton. a 

WHERE  THE  WEEVILS  FIRST  APPEAR. 


It  has  been  frequently  observed  in  all  parts  of  the  State  that  the 
weevils  first  appear  on  the  cotton  field  along  the  side  adjoining  wood- 
land, if  there  be  any  timber  adjoining.  From  the  extensive  reports 
of  observers  thruout  the  State  there  seems  to  be  no  doubt  that  cotton 
in  timbered  sections  is  much  more  seriously  injured  by  the  weevil 
than  that  on  prairie  land,  owing  to  the  more  successful  hibernation  in 
the  timber.  It  has  also  been  observed  by  many  that  the  weevils  first 
appear  and  commence  to  be  injurious  in  that  part  of  the  field  where 
they  were  most  abundant  during  the  previous  year.  In  southern 
Texas  the  weevils  may  be  found  on  stubble  cotton  very  earty  in  the 
season;  in  fact  practically  all  winter.  They  hardly  seem  to  hibernate 
in  the  strict  sense  of  the  word,  as  under  such  conditions  they  are 
found  feeding  on  warm  days  practically  thruout  the  winter. 

Upon  emerging  from  hibernation  the  majority  of  the  early  weevils 
seek  the  earliest  cotton,  which  may  be  either  stubble  cotton  or  planted, 
and  they  will  be  found  more  abundant^  upon  it  than  elsewhere,  even 
tho  the  early  cotton  forms  but  a very  small  part  of  the  acreage  on  a 


a The  same  value  of  rotation  has  been  noted  by  Mr.  Louis  Teltschick  at  Vienna. 
(See  Mally,  Report  on  Boll  Weevil,  1902,  p.  66,  paragraph  4.) 


HIBERNATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL. 


25 


large  plantation,  and  altho  later  cotton  may  be  up,  but  still  small. 
Having  assembled  upon  the  early  cotton,  most  of  these  weevils  seem 
to  stay  upon  it  until  it  squares,  and  they  do  not  spread  generally  to 
the  later  cotton  until  it  also  commences  to  square.  This  habit  must  be 
taken  into  consideration  in  estimating  the  number  of  weevils  upon  a 
given  area  in  the  spring,  for  if  the  cotton  be  not  planted  at  the  same 
time  over  the  entire  place,  neither  the  earliest  cotton  nor  that  planted 
later  will  give  a fair  idea  of  the  number  of  weevils  which  have  hiber- 
nated successfully.  The  total  area  must  be  taken  into  consideration 
and  the  average  for  the  whole  place  estimated  by  duly  weighting  the 
number  found  upon  the  acreage  of  both  early  and  late  planting.  By 
the  time  the  majority  of  hibernated  weevils  emerge,  however,  the 
medium  and  late-planted  cotton  will  be  so  far  advanced  as  to  hold  the 
weevils  near  where  they  emerge,  and  no  further  concentration  may 
be  expected. 

SUMMER  BROODS  OF  THE  WEEVIL. 

The  first  summer  brood  of  weevils  from  eggs  deposited  by  the 
hibernated  adults  begins  to  emerge  from  squares  during  the  last  ten 
days  in  May  in  southern  Texas,  and  farther  north,  in  central  and 
northern  Texas,  continues  emerging  during  J une  and  the  first  ten  days 
in  July.  Thus  in  Lavaca  County  there  is  a marked  increase  in  the 
number  of  weevils  found  in  the  field  after  June  1 or  sometimes  during 
the  last  week  of  May.  In  1901  Mr.  Teltschick  secured  2,136  weevils 
up  to  the  third  week  of  May  on  10  acres*  the  maximum  appearing 
during  the  second  week  of  May;  but  during  the  last  week  of  May  he 
secured  on  the  same  area  2,114  weevils,  or  very  nearly  as  many  as 
during  the  whole  spring,  showing  that  the  first  new  brood  was  then 
emerging.  In  1903,  up  to  June  1,  on  three-fourths  of  an  acre  of  trap 
rows  he  had  picked  241,  with  a maximum  on  May  18;  but  on  June  1 
he  secured  368,  and  during  the  month  of  June  1,759,  with  the  maxi- 
mum number  on  the  15th.  In  1904,  on  the  one-fourth-acre  plot  pre- 
viously mentioned  he  secured  453  up  to  June  1,  the  maximum  number 
of  150  on  May  23;  but  on  June  4 250  were  secured  and  146  on  June 
18.  Mr.  Teltschick  writes  as  follows: 

In  my  opinion  very  few  weevils,  if  any,  matured  from  punctured  squares  before 
June  either  in  this  or  previous  years  in  this  section.  Cotton  planted  here  March  1 
(this  is  as  early  as  any  is  planted,  the  greater  bulk  never  being  planted  before  April 
1)  as  a rule  begins  to  form  squares  on  April  25.  It  requires  the  squares  at  that  time 
from  two  to  three  weeks  to  grow  large  enough  to  provide  the  food  necessary  for  the 
development  of  the  weevil.  The  squares  are,  of  course,  being  punctured  as  soon  as 
they  form,  and  I doubt  whether  any  eggs  are  deposited  in  them  so  long  as  they  are 
too  small  to  permit  the  weevil  secreting  itself  within  the  involucre. 

At  College  Station  the  first  fallen  squares  were  found  on  June  17, 
1904.  The  first  weevils  from  these  squares  emerged  J une  23  and  the 


26 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


last  on  J une  29.  At  Terrell,  Tex. , the  first  brood  commenced  to  emerge 
on  June  30  and  the  last  of  these  was  secured  on  July  12. 

Altho  the  hibernating  weevils  may  continue  to  oviposit  for  some 
time  there  seems  to  be  but  little  overlapping  in  the  appearance  of  the 
first  and  second  generations  of  weevils.  There  is  a period  from  the 
first  to  the  middle  of  July  thruout  the  greater  part  of  the  infested 
area  when  but  little  damage  is  reported  from  the  weevil  and  when  but 
few  weevils  are  found.  This  is  the  period  during  which  the  second 
brood  is  developing  within  the  squares.  About  the  middle  of  July 
and  during  the  next  ten  days  the  second  brood  of  weevils  appears  and 
is  generally  reported.  In  some  instances  the  injury  by  the  second 
brood  is  serious,  especially  where  large  numbers  have  hibernated  suc- 
cessfully, and  after  the  second  brood  appears  practically  all  the  squares 
become  punctured  and  no  more  cotton  is  made.  This  condition  is 
more  common  in  southern  Texas,  but  usually  the  injury  by  the  second 
brood  is  no  more  serious  than  that  due  to  the  first  in  late  J une,  and  in  a 
great  many  cases  it  is  reported  as  being  decidedly  less.  In  general, 
unless  there  be  exceptional  rains,  the  hot  suns  of  July  seem  to  check 
the  development  and  injury  of  the  weevil. 

The  distinction  betw  een  the  second  and  third  broods  is  not  so  marked. 
The  period  of  oviposition  of  the  second  brood  doubtless  being  longer 
than  that  of  the  first,  the  third  brood  commences  to  appear  before  the 
last  of  the  second  brood  has  emerged.  However,  there  is  still  a very 
decided  and  notable  increase  in  the  number  of  weevils  from  the  first 
to  the  middle  of  August,,  depending  upon  the  latitude  and  season. 
This  is  generally  noticed,  and  commonly  reported  as  the  third  brood. 
Usually  with  the  emergence  of  this  brood  the  weevils  have  become 
sufficiently  numerous  to  destro}^  all  the  squares  as  they  form  so  that 
no  more  blooms  are  seen.  From  this  time  the  weevils  attack  the 
maturing  bolls  much  more  frequently.  After  the  appearance  of  the 
third  brood  the  different  generations  become  so  involved  that  it  is 
impossible  to  distinguish  between  them. 

At  Terrell,  Tex.,  five  distinct  broods  were  reared  in  1904  up  to 
October  3,  and  these  weevils  then  commenced  to  oviposit,  so  that 
there  would  doubtless  have  been  a maximum  of  six  complete  broods 
in  that  localit}^.  The  records  at  Terrell  are  as  follows:  From  the  first 
fallen  squares  injured  by  the  hibernated  brood,  weevils  emerged  on 
June  30,  Jul}-  5,  and  July  12.  On  July  5 these  weevils  were  placed 
in  a cage  upon  fresh  squares,  and  the  weevils  developing  from  these  I 
squares  emerged  on  July  22,  or  in  from  17  to  22  days.  These  were  1 
placed  on  squares  on  July  23,  and  the  weevils  from  them,  or  the  third  0 
brood,  emerged  August  17  to  20,  or  in  25  to  28  days.  These  weevils  | 
were  placed  on  squares  August  20,  and  the  weevils  developing  from  H 
them,  or  the  fourth  brood,  emerged  September  8 and  9,  or  in  19  to  20  j' 
days.  These  were  placed  on  squares  September  10,  and  the  weevils  I 


HIBERNATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL. 


27 


developing  from  them,  or  the  fifth  brood,  emerged  October  3,  or  in 
23  days.  In  all  cases  this  period  of  development  includes  to  a greater 
or  less  extent  the  feeding  period,  which  must  precede  oviposition. 

Practically  the  same  number  of  generations  seems  to  occur  at  Col- 
lege Station.  Altho  we  have  not  determined  this  by  rearing  weevils 
as  rapidly  as  possible  thruout  the  season,  the  field  records  show  the 
first  three  broods  very  distinctly,  and  during  the  fall  there  seem  to  be 
three  more  broods  between  September  1 and  the  time  of  hibernation. 
The  number  of  broods  after  September  1 is  very  largely  controlled 
by  the  temperature  and  rainfall,  which  combine  to  affect  the  food  sup- 
ply and  the  mortality  of  the  developing  weevils.  It  is  probable,  how- 
ever, that  in  a late  season  seven  broods  might  develop  at  College 
Station,  as  the  field  records  (see  page  10,  Table  II,  for  1903)  show  the 
weevils  (probabl3T  of  the  sixth  maximum  brood)  to  have  been  freely 
ovipositing  early  in  November,  and  if  frosts  did  not  occur  until  late 
in  that  month  a large  number  of  these  would  probably  emerge. 

In  southern  Texas,  Hunter  and  Hinds  have  shown  that  with  the 
average  season  of  reproductive  activity,  extending  from  May  1 to 
November  15,  eight  generations  may  be  produced  during  the  year. 
Thus  there  is  probably  a difference  of  two  broods  in  the  maximum 
number  of  generations  between  southern  Texas  and  northern  Texas, 
but  this  difference  will  not  materially  affect  either  the  injury  by  the 
weevil  or  the  number  of  weevils  going  into  hibernation,  as  the  weevils 
seem  to  reproduce  in  practically  the  same  length  of  time  in  northern 
Texas  as  in  southern  Texas,  the  summer  temperature  being  nearly  the 
same,  and  after  the  third  brood  they  are  sufficiently  numerous  in  either 
section  to  prevent  the  further  fruiting  of  the  crop.  Nevertheless, 
factors  aside  from  a difference  in  the  number  of  generations  will  prob- 
ably cause  less  damage  in  northern  Texas. 

By  September  1 to  15  the  weevils  usually  reach  the  maximum  num- 
ber and  during  the  fall,  as  before  observed,  their  number  depends 
primarily  on  the  food  supply  and  weather  conditions,  so  that  the  num- 
ber going  into  hibernation  depends  on  local  conditions.  The  difference 
in  the  amount  of  injury  which  the  weevil  may  do  in  central  or  northern 
and  in  southern  Texas  will  depend  therefore,  first,  upon  the  smaller 
number  of  weevils  hibernating  successfully  and,  second,  upon  their 
appearing  later  in  the  spring  so  that  the  cotton  may  be  able  to  make  a 
more  rapid  growth  in  comparison  with  the  development  of  the  early 
broods  of  the  weevil  under  the  high  temperatures  prevailing  during 
early  summer  in  northern  Texas  than  will  be  the  case  farther  south  in 
late  May.  But  it  is  not  probable  that  the  mere  number  of  broods  will 
make  any  material  difference  in  the  amount  of  injury.  The  first  three 
broods  seem  to  be  well  defined,  as  is  clearly  shown  by  the  numerous 
reports  of  our  voluntary  observers  and  by  the  reports  of  the  observers 
of  the  crop  service  of  the  U.  S.  Weather  Bureau.  The  amount  of 


28 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


injury  done  depends  upon  the  abundance  of  these  broods,  which 
depends  largely  upon  the  time  of  appearance  and  also  upon  the  relative 
abundance  of  the  hibernating  brood. 

MORTALITY  OF  SUMMER  BROODS. 

The  mortality  occurring  in  summer  and  fall  broods  may  properly 
be  distinguished  from  that  among  weevils  which  hibernate,  for  in  the 
summer  the  greatest  mortality  occurs  in  the  immature  stages.  The 
number  of  weevils  developing  from  squares  in  which  eggs  have  been 
laid  is  shown  in  Table  IV. 


Table  IV. — Percentage  of  weevils  from  infested,  squares. 


Date. 


Where  picked  and  how  kept. 


Number 
of  squares. 

Per  cent 
emerged. 

Weighted 
per  cent 
emerged. 

11,250 

23.5 

23.5 

1,522 

39 

675 

30 

350 

34 

377 

23 

2,924 

34.3 

14, 174 

25.7 

162 

40 

40 

200 

39.5 

43 

30 

243 

37.8 

405 

38.7 

400 

9.0 

9.0 

210 

2.3 

68 

2.9 

354 

0 

91 

1.1 

1.1 

1,123 

3.9 

May  —1902 

July  8, 1904 

Sept.  10, 1903 
Sept.  — , 1903 
Sept.  21, 1903 

Total  of 

Total  of 

Sept.  — , 1903 
Sept.  21,1903 

do 

Total  of 

Total  of 

July  15, 1904 

Sept.  11,1903 
Sept.  22, 1903 
Sept.  11,1903 
Sept.  21,1903 


Picked  from  ground;  placed  in  cloth  bags 
and  kept  in  laboratory  under  dry  condi- 
tions   

Picked  from  ground;  kept  under  fairly 

normal  conditions 

do 

,...  .do 

do 


lots  2,  3,  4,  and  5 ... 
lots  1,  2,  3,  4,  and  5 . 


Picked  from  plants;  « kept  on  moist  soil 

Picked  from  ground;  kept  between  shaded 

rows 

do 


lots  7 and  8 

lots  6,  7,  and  8. 


Picked  from  ground,  under  screen;  placed 

in  part  sun 

Picked  from  ground;  placed  in  sun 

Picked  from  plants;  n placed  in  sun 

Picked  from  ground;  placed  in  sun 

Picked  from  plants;  a placed  in  sun 


Total  of  lots  9,  10,  11,  12,13. 


a Picked  from  plants  when  squares  would  drop  off  by  touching  them. 


Lot  1 is  based  upon  the  following  note  made  by  Mr.  Wilmon 
Newell.  During  May,  1902,  Professor  Mally  gathered  infested  squares  i 
in  fields  along  the  Brazos  River  below  Wellborn.  About  1^  bushels  || 
of  these  squares  were  brought  to  College  Station,  sewn  up  in  cheese:cloth 
sacks,  and  weevils  allowed  to  hatch.  June  15  the  weevils  were  picked 
out  and  by  careful  measurement  there  were  115  c.  c.  of  them,  and  15 
c.  c.  contained  315  weevils,  or  1,763  weevils  to  a bushel.  Subsequently  ;! 
we  have  found  about  7,500  squares  in  a bushel,  thus  indicating  that 
only  about  23.5  per  cent  produced  weevils.  The  squares  were  kept 
in  the  laboratory  in  a dry  place,  and  the  lack  of  moisture  may  proba- 
bly account  for  the  low  percentage  producing  adults.  In  another 
test  2,921  squares  gave  a weighted  average  of  31  per  cent  producing 
weevils.  These  were  picked  up  and  kept  under  fairly  normal  condi- 


HIBERNATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL. 


29 


tions.  From  405  squares  which  were  kept  on  moist  soil  or  between 
shaded  rows  weevils  were  developed  from  38.6  percent,  but  where  the 
squares  were  left  in  the  hot  sun,  among  1,123  squares  but  1 per  cent 
produced  weevils.  This  shows  strikingly  the  value  of  having  rows 
wide  apart  so  that  the  sun  may  strike  the  fallen  squares. 


Table  V. — Percentage  of  mortality  of  weevils  at  different  stages  of  development. 


Lot. 

Date. 

Picked 

from— 

Condition. 

Number  of 
squares. 

Dead. 

Alive. 

Weevils 
| emerged.  | 

Possible  to 
emerge. 

Squares 
dry.  1 

8* 

Y 

c3 

ft 

8 

ft 

ft 

j Weevils. 

Total. 

Larvse. 

8 

0 

ft 

| Weevils. 

o 

H 

1 

Aug.  12 

133 

36.3 

1.5 

2.2 

28 

4 

24 

56 

2 

July  14 

do 

572 

44 

2 

3 

23 

11 

17 

51 

1904. 

3 

July  8 

do  . . . 

1,522 

57.6 

3.4 

... 

39 

39 

4 

Sept.  11 

do 

In  shaded 

200 

60 

0.5 

39.5 

39.5 

rows. 

5 

Sept.  22 

do  ... 

do 

43 

69 

7 

2 

21 

30 

6 

Sept.  21 

do  ... 

In  sun 

210 

64 

32  1 

0.6 

1.4 

0.5 

2. 5 

7 

do 

do  . . . 

do 

68 

92.8 

1.4 

4.4 

1.4 

7.2 

8 

...  .do  . . . 

do  . . . 

Squares 

100 

61 

18 

3 

2 

1 

3 

1 

10 

15 

brown. 

9 

do  ... 

do ... 

Squares 

268 

65 

5.61.5 

0.7 

11 

9 

1.8 

21.8 

4.8 

26.6 

green. 

10 

Sept.  11 

Plants . . 

do.  a .. 

400 

59.5 

1.8,0. 5 

«6. 8 

1 

30.5 

31.5 

Lots  6-10 

, weighted 

1 average... 

1,046 

63 

10 

i 

3 

77 

5.4 

3.1 

0.5 

9 

14.8 

Average  of  sou  ares  in  whieh 

26 

3 

8 

37 

14 

10 

1 

25 

39 

some  si 

;age  is  fou 

nd. 

1904. 

11 

Oct.  5 

Plants  a . 

Squares 

100 

44 

44 

55 

1 

56 

0 

green. 

Remarks. 


Counted  just 
from  field. 
Do. 


Allowed  to 
emerge. 

Do. 

Partly  al- 
lowed to 
emerge. 

Do. 


Do. 

Counted  just 
from  field. 
Do. 

Allowed  to 
emerge. 


Seven  died  in 
emerging. 


Counted  just 
from  field. 


a Squares  picked  from  plants  when  just  ready  to  drop. 


The  count  made  on  October  5,  1904,  fully  confirms  this.  These 
squares  were  picked  from  the  plants,  taking  those  that  would  drop 
into  the  hand  when  touched,  as  in  previous  similar  work.  An  imme- 
diate examination  showed  that  55  per  cent  contained  live  larvse  of 
various  sizes,  but  mostly  about  half  grown.  Tho  a few  were  ready  to 
pupate,  but  one  pupa  was  found,  while  there  were  14  in  which  the  work 
of  young  larvae  was  clearly  recognizable  but  in  which  no  larva  could 
be  found.  All  squares  showed  egg  punctures,  but  no  eggs  could  be 
found  in  them. 

The  time  at  which  the  greatest  mortality  in  the  development  of  the 
weevil  occurs  is  a matter  of  some  practical  importance  and  the  data 
given  in  Table  V throw  considerable  light  upon  this  point.  We  have 
but  few  observations  as  to  the  mortality  in  the  egg  stage,  but  Hunter 
and  Hinds  state  that  but  few  eggs  fail  to  hatch,  which  we  have  found 
to  be  the  case  in  the  laboratory.  As  the  square  receiving  an  egg  does 


30 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


not  fall  for  about  10  days  and  remains  green  long  after  the  hatching 
of  the  egg,  which  takes  place  in  about  2.5  days,  there  seems  no  reason 
to  suspect  any  considerable  mortality  at  this  period.  After  the  infested 
squares  have  dried  or  decayed  it  becomes  very  difficult  to  find  any 
trace  of  larvae  which  die  before  they  are  half  or  two-thirds  grown. 
The  table  shows  that  in  about  63  per  cent  of  the  infested  squares  no 
trace  of  weevil  stage  could  be  found.  In  this  percentage  are  the 
squares  which  had  received  feeding  punctures  only  and  a large  num- 
ber showing  external  signs  of  egg  punctures,  thus  indicating  that  a 
great  mortality  occurs  while  the  larvae  are  less  than  half  grown.  Fur- 
thermore, it  will  be  observed  that  of  those  individuals  which  pass  the 
larval  stage  succesfully  1.6  per  cent  died  in  the  squares  or  while  emerg- 
ing. It  has  previously  been  shown  that  only  about  1 per  cent  of 
squares  placed  where  fully  exposed  to  sunshine  developed  weevils,  j 
It  would  therefore  appear  that  the  mortality  was  largely  due  to  the  1 
squares  becoming  so  dried  that  the  food  supply  was  cut  off  from  the 
young  larva.  Hence,  it  would  seem  that  the  sooner  the  square  falls  ! 
after  being  punctured,  the  higher  will  be  the  mortality,  provided  the 
ground  is  not  shaded  by  close  rows,  and  that  any  means  for  knocking 
off  the  squares  before  they  would  naturally  fall,  or  a variety  or  strain 
of  cotton  which  sheds  its  squares  more  quickly  after  being  punctured, 
will  be  of  decided  advantage  in  increasing  the  mortality  of  the  weevil. 
This  seems  to  be  even  more  marked  where  the  squares  are  covered  by  ; 
the  soil  as  is  shown  in  Table  VI. 


Table  VI. — Percentage  of  mortality  of  weevils  in  squares  buried  in  soil. 


3 

Date. 

Depth 

buried. 

Condition. 

Number  of  squares. 

Per  cent  dead. 

Per  cent 
alive. 

a 

c 

s- 

a 

P- 

Squares  dry  or  de- 
cayed. 

3 

A 

j Pupae. 

Weevils  in  square. 

| Weevils  in  soil. 

Total. 

[ Larvae., 

a l 

p 

Ph 

Weevils  in  squares. 

From  squares. 

1 

Aug  15 

5 inch 

Kept  moist  in  laboratory. 

a 25 

2 

do 

1 inch 

do 

<<  25 

3 

do 

Is  inches. . 

do 

a 25 

4 

Aug.  29 

1 inch 

do 

a 25 

72 

4 

4 

24 

5 

do 

1*-  inches.. 

do 

a 25 

28 

4 

12 

44 

38 

6 

Sept.  21 

11  inches.. 

In  field 

50 

74 

2 

76 

8 

7 

do 

2 j inches.. 

Rather  dry 

78 

75 

4 

9 

b 88 

4 

1 

8 

4 inches 

do 

200 

clOO 

A 

...!.do 1 

( )n  surface 

In  sun 

180 

85 

15 

0 

B 

Sept.  18 

do 

174 

62 

26 

12 

0 

c 

July  15, 1901. 

do .... 

Under  screen 

400 

91 

9 1 

....  .do 

1 inch 

Rather  wet 

400 

94. 5 

3 

10 

do 

2 inches  . . 

do 

ion 

81 

10 

11 

do  . 

3 inehes 

. . .do 

400 

92. 5 

12 

do 

4 inches  .. 

do 

400 

95 

3 

0.5 

a Contained  larvae  or  pupae  when  buried, 
ft  Dead  weevils  eaten  by  ants;  squares  green. 
o Ants’  nest  just  beneath. 


HIBERNATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL. 


31 


It  is  frequently  asserted  that  frequent  cultivation  is  of  value  against 
the  weevil  in  that  the  immature  stages  are  killed  covering  the 
squares  with  soil.  The  data  given  in  Table  VI  hardly  confirm  this. 
Rarely  will  squares  be  buried  over  1 or  2 inches.  Lots  1,  2,  3,  4,  5, 
9,  and  10  show  that  the  mortality  in  squares  buried  at  this  depth  is 
about  the  same  as  under  normal  conditions.  Lots  6 and  T seem  to  show 
a benefit  from  burial,  but  these  were  placed  in  rather  dry  soil  in  the 
field  in  open  sun,  and  when  compared  with  lots  A and  B on  the  sur- 
face it  is  seen  that  the  burying  insured  a greater  per  cent  developing. 
It  seems  safe  to  say  that  in  no  case  will  burial  for  not  over  2 inches 
result  in  any  great  mortality,  and  that  in  all  probability  the  percent- 
age of  weevils  developing  will  be  greater  than  if  left  exposed  to  the 
sun  on  the  surface.  It  is  more  frequently  claimed  that  by  plowing 
squares  under  deeply  after  a good  rain  the  moist  soil  will  rot  them 
and  the  weevils  will  be  unable  to  escape.  Unfortunately  we  have 
no  conclusive  tests  upon  this  point,  but  it  would  seem  that  a suffi- 
ciently deep  plowing  to  bury  squares  4 inches  just  after  a rain  would 
be  such  a decidedly  bad  agricultural  practise  as  to  possibly  offset  any 
benefit  that  might  be  derived  from  destroying  the  weevils  in  the 
squares  buried. 

RATE  OF  INCREASE  OF  THE  WEEVIL. 

Hunter  and  Hinds  have  shown  that  a female  weevil  normally  lays 
some  150  eggs  during  an  average  of  about  54  days,  and  that  nearly 
one-half  of  the  eggs  are  deposited  during  the  first  third  of  the  period 
of  oviposition.  Allowing  24  days  for  the  development  of  the  average 
adult  and  18  days  for  the  oviposition  of  one-half  of  the  eggs,  they  also 
estimate  that  the  average  length  of  a generation  is  about  42  days. 
The  sexes  of  the  weevil  are  produced  in  about  equal  numbers.  With 
these  factors  as  a basis  we  may  easily  compute  that  if  on  June  1 there 
were  an  average  of  2 weevils  to  100  stalks  of  cotton,  on  July  15,  at  the 
end  of  the  first  theoretical  brood,  there  would  be  50  weevils;  and  that, 
if  one-half  of  these  were  females  and  the  usual  percentage  survived, 
on  September  1 there  would  be  1,250  weevils  to  100  stalks.  But  these 
computations  make  no  allowance  for  the*  mortality  in  the  immature 
stages,  and  extended  observations  in  the  field  show  that  such  rapid  multi- 
plication does  not  really  occur.  It  has  been  ascertained  by  the  writer 
that  the  first  brood  of  weevils  rarely  numbers  more  than  five  times  the 
hibernated  brood,  and  at  College  Station  often  but  two  or  three  times. 
At  Vienna,  in  1903,  Mr.  Teltschick  picked  241  weevils  from  his  trap 
rows  up  to  June  1,  while  on  June  1 to  7, 15,  and  22  he  picked  759  weevils 
on  the  same  area.  This  doubtless  represents  very  accurately  the  increase 
of  the  first  brood  over  the  hibernated  weevils,  showing  an  increase  of  315 
per  cent.  It  is  of  course  probable  that  some  weevils  had  left  the  trap 
rows  for  the  planted  cotton,  which  was  barely  commencing  to  square 


32 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


on  June  22,  but  the. number  would  have  been  comparatively  small 
and  the  end  of  the  generation  was  probably  considerably  later,  so 
that  an  increase  of  ten  times,  or  1,000  per  cent,  would  be  a conserva- 
tive estimate.  The  largest  number  of  weevils  at  College  Station  early 
in  July  was  found  on  EckoPs  cotton,  which  was  planted  very  early, 
on  July  14,  1904,  when  there  were  27  weevils  to  100  stalks.  This  field 
was  adjoining  a gin  and  1 mile  away,  on  Ayer’s  cotton,  there  were  but 
15  weevils  to  100  stalks.  On  the  same  date,  on  the  Brazos  River,  there 
were  but  10  weevils  to  100  stalks,  and  on  our  experimental  plats, 
where  the  stalks  were  destroyed  the  previous  fall,  the  hibernated 
brood  had  numbered  barely  1 weevil  to  100  stalks.  There  were  but 
3.3  weevils  of  the  first  brood  to  100  stalks.  Accurate  figures  for  the 
rate  of  increase  from  the  first  to  the  second  brood  are  not  available, 
but  from  general  observations  and  from  reports  of  the  injury  done  by 
the  second  brood,  as  compared  with  the  first,  it  is  safe  to  assert  that 
the  rate  of  increase  is  not  materially  greater  for  the  second  brood  than 
for  the  first.  The  rate  of  increase  of  the  third  brood  seems  to  be 
decidedly  greater,  but,  as  the  late-developing  individuals  of  the  second 
brood  and  the  first  of  the  third  brood  more  or  less  overlap,  it  is  diffi- 
cult to  determine  this  accurately  in  the  field.  However,  the  total 
increase  at  the  appearance  of  the  third  brood  over  the  number  of 
hibernated  individuals  can  be  given  in  one  or  two  cases.  Along  the  ! 
Brazos  River,  in  1903,  there  were  but  2 weevils  to  100  stalks  on 
June  17,  and  on  August  25  47  weevils  to  100  stalks,  or  an  increase 
of  twenty-three  times  between  these  dates,  the  collection  at  the  latter  j 
date  probably  representing  part  of  the  fourth  brood.  In  1903,  at  the  > 
college  on  our  experimental  plats,  there  were  5.5  weevils  to  100  stalks  ; 
on  August  13  where  there  were  1.5  on  June  18,  representing  the 
hibernated  brood.  The  greatest  increase  we  have  observed  from  the 
hibernated  brood  until  the  middle  of  August  was  on  the  plat  of 
the  experiment  station  at  the  college  barn  in  1903,  where  there  were  5 
hibernated  weevils  to  100  stalks  on  June  18  and  233  on  August  13,  or 
an  increase  of  forty-seven  times.  From  a careful  study  of  the  data  it 
seems  safe  to  assert  that  the  usual  rate  of  increase  from  the  second  to 
the  third  brood  is  not  over  ten  or  fifteen  times  in  this  section,  as  there  ! 
is  usually  not  over  1 weevil  to  the  stalk  of  cotton  until  after  mid- 
August.  It  will  be  seen,  therefore,  that  tho  the  theoretical  increase 
of  the  weevil,  based  upon  a careful  study  of  its  habits  and  the  mor- 
tality as  far  as  can  be  ascertained,  would  show  an  increase  of  twenty- 
five  times  from  between  the  first  and  second  and  second  and  third 
theoretical  broods  of  42  days  each  from  June  1 to  September  1,  as  a 
matter  of  fact,  during  the  first  period  mentioned,  the  increase  up  to 
and  including  the  second  brood,  emerging  about  the  third  week  in 
July,  is  usually  considerably  less  than  twenty-five  times  the  hibernated 
brood  probably  not  over  fifteen  times — and  that  the  total  increase 


HIBERNATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL.  33 


from  the  1st  of  June  to  the  1st  of  September  is  only  about  fifty  times, 
certainly  not  over  sixty-five  times,  where  theoretically  it  would  be  six 
hundred  and  twenty-five  times.  The  reason  for  this  discrepancy  is 
unknown  to  the  writer,  but  is  a fact  for  which  the  cotton  planter 
should  be  decidedly  thankful.  It  may  be  that  the  mortality  of  the 
immature  stages  of  the  weevil  in  the  squares  is  greater  than  the  count 
of  thousands  of  squares  has  shown,  that  many  of  the  adult  weevils  die 
or  are  destroyed  before  reproducing,  or  that  the  number  of  eggs  laid 
and  the  length  of  the  period  of  oviposition  in  the  field  are  much  less 
than  those  observed  in  the  laboratory.  That  this  is  true  of  the  hiber- 
nated brood  is  shown  on  page  12.  It  would  seem  that  the  discrepancy 
is  mostly  due  to  the  two  latter  factors.  This  discrepancy  but  empha- 
sizes the  necessity  for  accurate!}"  observing  the  field  conditions  on  a 
very  large  scale  in  different  fields  in  different  sections  of  the  State 
constantly  thruout  the  season  if  we  are  to  obtain  accurate  knowledge 
of  the  true  habits,  rate  of  increase,  and  injury  of  the  boll  weevil,  as  it 
occurs  in  the  field. 

To  summarize  briefly,  it  would  seem  that  if  there  be  2 weevils  to 
100  stalks  of  the  hibernated  brood,  then  by  early  in  August  there  will 
be  a sufficient  number  of  weevils  to  stop  the  blooming  of  the  cotton. 
Furthermore,  with  the  normal  increase  it  seems  that  in  about  a month 
after  4 or  5 weevils  are  found  on  100  stalks,  there  will  have  been  suffi- 
cient increase  to  prevent  further  fruiting  of  the  cotton,  and  there  will 
then  be  from  75  to  100  weevils  to  100  stalks.  The  utter  impossibility 
of  making  a cotton  crop  where  a large  percentage  of  the  weevils  sur- 
vive the  winter  will  therefore  readily  be  seen  unless  exceptional  meas- 
ures can  be  taken  to  check  their  multiplication.  Weather  conditions 
unfavorable  to  the  development  of  the  weevils  are  decidedly  the  most 
important  controlling  factors,  and  that  such  conditions  not  infrequently 
occur  is  shown  by  the  reports  of  voluntary  observers  in  southern 
Texas  in  1904. 

INJURY  TO  SQUARES  IN  RELATION  TO  THE  NATURAL  INCREASE  OF 

SQUARES. 

The  formation  of  squares  upon  the  cotton  plant  depends  upon  so 
many  different  factors  that  it  is  exceedingly  difficult  to  make  any  gen- 
eral statements  regarding  the  increase  in  their  numbers.  Thus  the 
character  of  the  soil,  the  nature  of  the  variety  of  cotton,  and  the  cli- 
matic conditions  prevailing  all  influence  the  formation  of  squares.  It 
may  be  clearly  seen  from  Tables  VII  to  X that  some  varieties  form 
squares  much  faster  than  do  others,  and  that  between  the  same  dates 
the  same  variety  will  not  produce  the  same  number  of  squares  in  dif- 
ferent places.  However,  from  an  examination  of  the  tables  we  may 
form  some  idea  of  the  natural  increase  of  the  squares  early  in  the 
season  during  the  critical  period  of  fruit  formation.  During  the  2 


34 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


weeks  following  the  formation  of  the  first  2 squares  the  number  of 
squares  will  increase  ten  or  twelve  times;  in  other  words,  there  will 
be  from  20  to  25  squares;  and  during  the  next  2 weeks  this  number 
will  increase  two  times,  or  at  the  end  of  the  month  there  will  be 
about  40  squares,  or  about  twenty  times  as  manias  at  the  beginning 
of  the  month,  when  there  were  but  2 squares.  At  the  end  of  the 
second  month  there  will  be  an  increase  of  about  two  times  over  the 
first  month,  or  there  will  be  approximately  100  squares  to  the  plant. 
During  the  first  third  of  the  third  month  the  number  of  squares 
usually  remains  about  constant,  but  after  that,  tho  squares  are  con- 
stantly forming,  there  is  a tendency  to  decrease  for  a time. 


Table  VII. — Progress  of  infestation  by  boll  weevil  and  production  of  fruit  upon  cotton 
plats  at  College  Station , Tex.,  in  1903. 


Variety, 


Jones  Im- 
proved . 


Allen 

Excelsior 

Parker 
Griffith... 
King 


June  18 
July  11 
July  27 
Aug.  12 
Sept.  5 
June  18 
July  11 
Aug.  12 
June  18 
July  11 
Aug.  12 
Sept.  5 
June  18 
July  11 
Aug.  12 
June  18 
July  11 
Aug.  12 
June  18 
July  11 
July  27 
Aug.  12 
Sept.  5 


Squares. 


20 
25 
30 
10 
5 
20 
25 
10 
20 
25 
10 
5 

20 
25 
10 
20 
25 
10 
20 
25 
50 
1047. 
5,57 


125 


0.9 

.7 

9.1 

56 


35 


15 

6.3 

6 

21 


50 


97 


Blooms. 


13 

12.7 

51 


Bolls. 


Wee- 

vils. 


4.6 

12 

6 


.5 


..  12 

8 6 


.24 

8.5 


30 


Yield  per  acre. 


Pounds  of  seed  cotton. 


Sept.  17 
Sept.  i7 


Sept.  16 
Sept,  i 6 
Sept.  17 


Sept.  16 


178 


290 


Oct.  20 


Oct.  20 


Oct.  20 
Oct.’  *20 


Oct.  20 


358 


HIBERNATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL, 


35 


Table  VIII. — Comparison  of  'progress  of  infestation  by  boll  weevil  and  production  of  fruit 
upon  variety  plats  on  Carson  & Smith’s  plantation , Brazos  River , Wellborn , Tex. , in 
1903. 


Plat. 


Variety. 


1.  ..  Native 


2  Territory 

3  Dickson. 

4  Schley.. 


5 Bohemian 


3,4,5. 


King 


8  Shine  . 

9  do 


8-9... 
8 

8-9... 

....do. 

10.... 

Shine  . 

11.... 

do. 

12.... 

do 

13.... 

do 

12-13. 

do. 

10-13. 

do 

14.... 

do 

15 do 

15-16 do 

17 Wellborn  . 


Date  of 
examin- 
ation. 


June  26. 
July  17. . 
Aug.  17. 
Aug.  25. 


June  26. 
July  17. . 
Aug.  25. 


June  26. 
July  20.. 
Aug.  17. 
Aug.  25. 
June  26. 
July20. . 
Aug.  17. 
Aug.  25. 
June  26. 
July20. . 
Aug.  17. 
Aug.  25. 


June  26. 
July  20.. 
Aug.  25. 


June  26 
— do  . . . 
July  20 
Aug.  25 


June  26 

do  . . . 

do ... 

July  17 
June  26 
July  17 
Aug.  17 


June  26 
■July  17 
-Aug.  25 


July  20 
Aug.  25 
June  26 
July  20 
Aug.  25 


a 

Squares  per  plant. 

1 

Bolls. 

Yield  per  acre. 

X 

0) 

CO 

'd 

1 

,d 

00 

M 

1 

Pounds  seed  cot- 
ton. 

I Number  of  stall 
ined. 

Number. 

| Punctured. 

o 

a 

d 

OP 

o 

Fh 

<0 

Ph 

Blooms  per  plan 

Per  plant. 

o 

0) 

O 

<0 

CL, 

1 

u 

<x> 

P4 

c n 

> 

0) 

<D 

First  picking, 
1 September  23. 

I Second  picking, 
October  27. 

Total. 

| Bales. 

100 

1.6 

0. 01 

0.6 

50 

12.0 

.04 

.3 

0. 14 

0.06 

0.0 

10 

65.0 

3.5 

5.3 

1.9 

16.9 

.0 

5 

70.0 

36.0 

51.4 

2.6 

21.2 

9.4 

20 

— 

270 

172 

442 

.27 

100 

1.0 

0 

.0 

50 

8.0 

.04 

.4 

.08 

.3 

.0 

5 

99.0 

33.8 

34.1 

3.0 

21.0 

11.0 

163 

121 

284 

.i7 

100 

0 

.0 

50 

28.0 

.08 

.3 

.48 

.92 

2.1 

10 

98.0 

7.8 

7.9 

3.2 

23.9 

.4 

5 

92.0 

39.6 

43.0 

2.0 

26.6 

.0 

40 

100 

.32 

0 

.0 

25 

20.0 

.08 

.4 

.2 

.4 

.0 

10 

70.0 

4.5 

6.4 

2.4 

8.3 

.0 

5 

94.0 

41.6 

44.4 

3.0 

15.0 

.0 

60 

100 

.73 

0 

.0 

.25 

10 

16.0 

.04 

.2 

.16 

.2 

.0 

80.0 

7.0 

8.7 

2. 1 

15.4 

.0 

14.7 

1 

5 

144.0 

81.0 

56.2 

2.0 

27.8 

| 80 

a 340 

.21 

100 

2.5 

.03 

1.1 

25 

58.0 

. 16 

.3 

1.52 

2.44 

.0 

.... 

5 

104.  0 

40.2 

38.6 

2..0 

42.0 

.0 

80 

b 509 

491 

b 1, 000 

1 .65 
1 

100 

2. 96 

.0 

0.0 

100 

3. 28 

.0 

0.0 

25 

65.0 

0.  36 

.5 

1.40 

3.  6 

.0 

5 

90.0 

37.4 

41.5 

3.8 

52.0 

.04 

40 

476 

1,471 

1,948 

1.21 

150 

3.3 

150 

1.6 

150 

2.2 

.0 

0.0 

50 

54.0 

.3 

.5 

.64 

1.58 

150 

.01 

.45 

50 

6l!  0 

.08 

. 1 

1.2 

1.  96 

10 

109.0 

6.8 

6.2 

2.6 

32.3 

.02 

10 

a 1,000 

. 65 

100 

4.7 

1.0 

2.1 

25 

110.0 

.44 

.4 

1.4 

4. 88 

4 

106.0 

33.9 

32.0 

(?) 

625 

603 

1,228 

.76 

25 

42.0 

.28 

.5 

.48 

.52 

5 

195.0 

79.8 

40.9 

4.0 

71.4 

100 

272 

413 

710 

.43 

100 

3.6 

.0 

.0 

25 

52.0 

.44 

.8 

.92 

1.92 

5 

109.0 

52.8 

48.4 

1.4 

100.6 

(?) 

494 

672 

1,167 

i 

a Average. 


b About. 


36 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC, 


Table  IX. — Comparison  of -progress  of  infestation  by  boll  weevil  and  production  of  fruit 
upon  plats  of  cotton  planted  at  different  dates  by  August  Scholl,  Hunter,  Tex.,  in  1903. 


eg 

Squares  per 

02 

M 

Yield  per  acre. 

Date  of  exami 
tion. 

02 

M 

plant. 

02 

O 

o 

Pounds  seed  cotton. 

Variety. 

When  plant* 

3 

02 

U 

o> 

& 

a 

£ 

Number. 

1 Punctured. 

Per  cent 
punctured. 

OJ 

o. 

CO 

a 

o 

o 

s 

Per  plant. 

Per  cent 
I punctured. 

Fh 

P< 

02 

G) 

G> 

Date. 

First  pick- 
ing. 

Date. 

Second  pick- 
ing. 

Total. 

Bales. 

Mar  1. 

May  30. . 
July  3.. 
Aug.  5.. 
Aug.  28. 
July  3.. 
Aug.  6.. 
Aug.  28. 
May  30. . 

140 

3.0 



15 

40.0 

4.0 

10.0 

195 

195.0 

84.2 

43.1 

2.2 

9.6 

37.5 

140 

Native 

Mar  .. 

Av. 

15 

i9.0 

3.06 

i6.  i 

24.0 

Sept.  26. 

171 

Dec.  1... 

142 

313 

.21 

5 

80.0 

33.0 

41.2 

2.0 

8.0 

20.0 

20 

King 

Apr.  1. 

Av. 

5.6 

6.0 

Sept.  26. 

210 

Dec.l... 

148 

358 

.24 

July  3.. 
Aug.  5.. 
Aug.  28. 
July  3.. 
Aug.  5.. 
Aug.  28. 
July  3.. 
Aug.  5.. 
Aug.  28. 
July  3.. 
Aug.  5.. 
Aug.  28. 
July  3.. 

50 

40.0 

3.8 

9.5 

5 

57.0 

31.6 

56.4 

1.8 

12.0 

20.0 

140 

Av. 

19.0 

Sept.  26. 

181 

Oct.  15. . 

278 

460 

.30 

Shinp 

Apr . . . 

50 

20.0 

. 7 

3.5 

5 

97.0 

42.0 

43.3 

2.0 

. 

10.2 

33.3 

120 

Native 

Apr. . . 

Av. 

50 

i2.0 

i.  62 

lL3.5 

|13. 0 

Sept.  26. 

150 

Dec.l... 

120 

270 

.18 

5 

53.0 

24.6 

46.4 

.6 

5.8 

27.5 

80 

Native 

Apr . . . 

Av. 

50 

23.6 

3.34 

1.4.5 

5.0 

Sept.  26. 

173 

Dec.l... 

57 

230 

.15 

5 

42.0 

19.6 

46.6 

1.0 

12.4 

24.1 

140 

Shine 

May  .. 

Av. 

100 

. 9 

11.0 

Sept.  26. 

366 

Nov.  1.. 

57 

423 

.28 

Aug.  5. . 
Aug.  28. 
July  3.. 
Aug.  5.. 
Aug.  28. 

5 

62.0 

18.2 

29.3 

.2 

2.4 

8.3 

160 

Av. 

3.0 

Dec.  1... 

80 

80 

.05 

Native 

May  1. 

100 

. 7 

5 

36.0 

16.2 

45.0 

.2 

.6 

33.3 

40 

2.0 

HIBERNATION  AND  DEVELOPMENT  OF  BOLL  WEEVIL.  37 


Table  X. — Comparison  of  progress  of  infestation  by  boll  weevil  and  production  of  fruit 
upon  plats  of  cotton  at  College  Station , Tex.,  in  1904. 


Yield  per  acre. 

d 

V*  cc 

; v ii  o. 

1 Pounds  seed  cotton. 

Variety. 

Date  of  examinatii 

Number  of  stalks. 

| Total  per  plant. 

| Total  punctured. 

Per  cent  punc- 
tured. 

Dropped. 

”3 

o 

H 

Per  plant. 

Perfect. 

Open. 

Total  per  plant. 

• 

Punctured. 

Total. 

Per  100  stalks. 

Date. 

j First  picking. 

Date. 

Second  picking. 

Total. 

Bales. 

May  22 
May  30 
June  17 

2,500 

2,500 

400 

2 

0.08 

O . 

2 

.08 

5 

5.5 

36 

1.6 

5 

S-S 

320 

3 

. 9 

m r< ' 

400 

400 

2 

.5 

8* 

June  27 

15 

12 

.2 

0 

174 



0.43 

55 

0. 13 

0 

0 

c ft 

July  13 
Sept.  12 
May  22 
May  30 
J une  9 

50 

39 

.35 

34 

166 

3.3 

307 

6.1 

1 

2 

25 

4.5 

98 

86 

(a) 

0 

455  99 

108 

36 

144 

Aug.28 

258 

Sept.  14 

‘252 

510 

.32 

bio 

Ph-2 

2,500 

2,500 

320 

1 

. .04 

10 

.4 

0 c 

>— 1 o3 

3 

.9 

June  15 

2,500 

400 

5 

toft 

June  17 

4.8 

21 

1.2 

1 

(«) 

0 

p . 

June  27 

380 

22 

14 

.2 

92 

164 

.43 

91 

.24! 

0 

July  13 
Sept.  12 
May  22 
May  30 
June  17 

50 

43 

18 

.83 

38 

178 

3.8 

309 

6.2 

2 

4 

25 

6.5 

142 

86 

<"> 

491 

23 

*83 

46 

184 

Aug.27 

313 

Sept. 10 

348 

661 

• 4 

js  to 

1,200 

4 

.3 

1,200 

50 

14 

1.  1 

9.7 

25 

5.1. 

7 

0 

(a) 

2 

0 

® §J 

June  9 

250 

.8 

fift 

June  27 

400 

25 

152 

1.5 

8 

53 

.13 

0 

0 

<v  L 

July  13 
Sept.  12 
June  7\ 

50 

33 

19 

1.1 

47 

243 

4.8 

226 

4.5 

2 

4 

pqp. 

25 

1.3 

27 

84 

(«) 

0 

700 

31 

*90 

37 

148 

Na- 

tive. 

200 

0 

0 

0 

June  17 

200 

3 

1 

Sept.  16 
June  7 

25 

'i.8 

34 

79 

(“) 

0 

217 

10 

36 

24 

96 

Na- 

tive. 

275 

29 

2 

June  17 

200 

;;;; 

32 

7 

3.5 

! 

June  29 

290 

20 

111 

3.8 

113 

190 

0 

0 

June  7 

530 

55 

8 

1.5 

Na- 

June 17 

200 

61 

1 

21 

10 

tive. 

June  29 

364 

16 

128 

2.7 

137 

156 

0 

0 

Sept.  16 
June  18 

25 

2.8 

65 

22 

91 

(a) 

147 

7.4 

39 

32 

128 

Na-. 

tive. 

100 

25 

1.1 

6 

6 

6 

July  14 
Sept.  16 
June  14 

40 

63 

1140 

71 

44 

395 

65 

1.6 

537 

13 

6 

15 

25 

3.2 

88 

(a) 

22 

265 

14 

85 

31 

124 

50 

22 

47 

6.1 

583 

14 

Na- 

June 29 

398 

41 

30 

1. 1 

154 

616 

0 

0 

tive.  ' 

July  14 
Sept.  16 

40 

18 

437 

57 

121 

55 

1.4 

419 

11 

27 

25 

9.5 

219 

92 

(a) 

211 

11 

72 

46 

184 

a Not  counted.  & Consisted  of  a large  number  of  varieties. 


Note. — The  five  plats  of  native  cotton  referred  to  were  planted  by  different  farmers  in  the  vicinity 
of  College  Station. 

The  proportion  of  squares  punctured  by  the  end  of  the  first  month 
after  squares  have  commenced  to  form  has  been  found  to  range  from 
2.5  to  10  per  cent.  It  is  usually  not  over  5 per  cent,  .and  an  average 
proportion  of  3 per  cent  would  be  more  nearly  correct.  Thus,  on  the 
Brazos  River,  July  13,  1904,  but  8 per  cent  of  the  squares  were  punc- 
tured. At  the  College  on  our  main  plats  less  than  1 per  cent  were 
punctured.  At  Eckol’s,  on  June  14,  1904,  6.1  per*  cent  were  punc- 
tured and  on  June  29  but  1.1  per  cent.  In  1903  at  the  College  not 
over  2 per  cent  were  punctured  during  the  first  month  of  square  for- 
mation. In  the  Brazos  bottom  in  1903  the  proportion  was  less  than  1 
per  cent.  In  1901,  on  June  17,  Mr.  Teltschick  reported  to  Professor 


38 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


Malty  that  10  per  cent  of  the  squares  were  punctured  upon  cotton 
which  had  been  squaring  for  5 weeks.  At  the  end  of  the  second 
month  of  square  formation  there  is  an  increase  of  from  ten  to  fifteen 
times  in  the  percentage  of  punctured  squares.  On  August  13,  1903, 
an  average  of  35  per  cent  of  the  squares  on  our  plats  were  punctured, 
and  on  August  25  on  Smith  & Carson’s  plantation  there  were  42  per 
cent.  On  August  13,  on  the  experiment  station  plat  at  the  College 
barn,  there  were  65  per  cent,  these  representing  the  injury  done  upon 
the  emergence  of  the  third  brood  of  weevils.  On  July  14,  1904, 
Eckol’s  and  Ayer’s  cotton  had  57  and  44  per  cent  punctured,  this 
being  about  2 months  after  the  first  squares  formed.  In  a general 
way,  it  seems  safe  to  say  that  usually  50  per  cent  of  the  squares  will 
be  punctured  by  about  2 months  after  the  cotton  commences  to  square, 
at  which  time,  as  we  have  seen,  there  would  normally  be  about  100 
squares  to  the  stalk.  With  the  appearance  of  the  third  brood  of  wee- 
vils early  in  August  the  percentage  of  injury  rises  rapidly,  and  by 
September  1 from  85  to  90  per  cent  of  the  squares  will  be  found  punc- 
tured, tho  it  is  rather  unusual  to  find  over  90  per  cent  of  the  squares 
punctured  in  this  section  when  they  are  carefully  counted.  In  1904, 
at  the  end  of  6 weeks  of  square  formation,  there  were  but  8 per  cent 
of  the  squares  punctured  along  the  Brazos  River,  tho  on  the  oldest 
cotton,  which  had  been  squaring  about  2 months,  where  the  weevils 
were  thickest,  40  per  cent  were  punctured.  When  one-half  of  the 
squares  are  punctured  it  may  be  readily  concluded  that  there  are 
probably  sufficient  weevils  present  to  prevent  any  more  squares  from 
forming  fruit.  It  will  be  seen,  therefore,  that  the  critical  period  in 
the  relation  between  natural  increase  of  squares  on  the  plant  and  the. 
increased  injury  by  the  boll  weevil  is  during  the  period  of  6 to  8 weeks 
after  first  squaring,  which  usually  coincides  more  or  less  closely 
with  the  time  between  the  appearance  of  the  second  and  third  broods 
of  weevils.  Thus,  if  we  consider  6 weeks  as  the  average  time 
required  for  cotton  to  begin  to  square  after  planting,  it  will  be  seen 
that  the  bulk  of  the  fruit  must  be  set  in  85  or  90  da}7s  after  planting. 
In  other  words,  it  may  be  readily  seen  that  to  escape  injury  by  the 
boll  weevil  cotton  must  be  so  grown  that  the  bolls  will  commence  to 
open  in  about  100  days  after  planting,  and  that  all  the  fruit  which 
will  probably  be  secured  must  be  set  within  45  days  after  the  squares 
begin  to  form.  The  advantage  of  early  planted  cotton  and  rapid 
maturing  varieties  becomes,  therefore,  very  apparent. 


O 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 
BUREAU  OF  ENTOMOLOGY  BULLETIN  NO.  63,  Part  II. 

L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau. 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL  . 
RELATED  AND  ASSOCIATED  INSECTS. 


N O T E S 


BIOLOGY  OF  CERTAIN  WEEVILS  RELATED 
TO  THE  COTTON  BOLL  WEEVIL. 


BY 

W.  DWIGHT  PIERCE, 

Special  Field  Agent. 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE. 

1907. 


LETTER  OF  TRANSMITTAL 


U.  S.  Department  of  Agriculture, 

Bureau  of  Entomology, 

Washington , D.  C. , September  19,  1906. 

Sir:  I have  the  honor  to  submit  a manuscript  entitled  “ Notes  on 
the  Biology  of  Certain  Weevils  Related  to  the  Cotton  Boll  Weevil,” 
prepared  by  Mr.  W.  Dwight  Pierce,  special  field  agent  in  this  Bureau. 
A number  of  weevils  more  or  less  closed  related  to  the  boll  weevil 
occur  in  the  United  States  and  there  seems  a possibility  that  from 
some  of  them  parasites  may  be  obtained  which  may  be  induced  to 
transfer  their  attacks  to  that  destructive  pest.  The  present  paper 
gives  some  results  of  investigations  carried  on  during  the  year  1905, 
and  I recommend  its  publication  as  Part  II  of  Bulletin  No.  63  of  the 
Bureau  of  Entomology. 

Respectfully,  F.  H.  Chittenden, 

Acting  Chief  of  Bureau. 

Hon.  James  Wilson, 

Secretary  of  Agriculture. 


CONTENTS. 


Introduction 

Anthonomus  disjunctus  Lee 

Anthonomus  fulvus  Lee 

Anthonomus  squamosus  Lee 

Lixus  musculus  Say 

Orlhoris  crotchii  Lee 


Page. 

39 

41 

41 

42 

43 

44 


ILLUSTRATIONS. 


Page. 

Plate  I.  Work  of  Lixus  musculus  and  Orthoris  crotchii.  Fig.  1. — Gall  of  Lixus 
musculus  and  exit  hole  of  adult  on  stem  of  Polygonum  pennsylvanicum.  Fig. 

2. — Gall  of  Lixus  musculus  and  entrance  hole  (closed)  of  pyralid  caterpillar 
on  stem  of  Polygonum.  Fig.  3. — Pod  of  Mentzelia  nuda  showing  two  egg 
punctures  of  Orthoris  crotchii.  Fig.  4. — Pod  of  Mentzelia  opened,  showing 
a cluster  of  Orthoris  crotchii  cells,  and  the  cocoons  of  Tetrastichus.  Figs. 

5,  6. — Interior  of  pod  of  the  same,  showing  several  cells  of  Orthoris  crotchii. 

Fig.  7. — An  isolated  cell  of . Orlhoris  crotchii , showing  the  manner  in  which 
t he  seeds  are  eaten 42 


ii 


U.  S.  D.  A.,  B.  E.  Bui.  63,  Part  II. 


C.  B.  W.  I.,  February  5,  1907. 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL  AND 
RELATED  AND  ASSOCIATED  INSECTS. 


NOTES  ON  THE  BIOLOGY  OF  CERTAIN  WEEVILS  RELATED  TO 
THE  COTTON  BOLL  WEEVIL. 

By  W.  Dwight  Pierce, 

Special  Field  Agent 

INTRODUCTION. 

During  the  year  1905  considerable  knowledge  was  gained  concerning 
the  biology  of  Texas  weevils.  The  practical  importance  of  this  infor- 
mation lies  in  the  possibility  that  from  some  of  these  species  parasites 
may  be  artificially  induced  to  transfer  their  activities  to  the  boll  weevil 
(Anthonomus  grandis  Boh.).  But  it  has  a further  interest  in  that  it 
makes  possible  a comparison  between  the  life  history  of  this  impor- 
tant enemy  of  cotton  and  that  of  related  insects  which  normally 
inhabit  regions  into  which  that  pest  has  onl}T  recently  made  its  advent. 

Anthonomus  grandis  breeds  during  the  entire  growing  season,  from 
April  to  October,  and  on  one  plant — cotton.  Its  host  plant  is  so  plen- 
tiful that  there  is  a constant  food  supply.  Anthonomus  signatus  Say, 
which  breeds  in  immense  numbers  in  the  flowers  of  strawberry,  black- 
berry, dewberry,  and  redbud,  is  not  known  to  have  more  than  the  short 
period  of  activity  limited  by  the  fruiting  of  its  host  plants.  Hence  the 
possibility  of  transferring  parasites  would  be  limited  to  a short  period 
and  there  would  be  further  difficulties  on  account  of  the  local  distribu- 
tion of  the  food  plants.  Anthonomus  xneotinctusQh&vwp.,  which  has 
been  found  to  breed  in  enormous  numbers  in  pepper,  in  western  Texas, 
is  not  known  to  occur  on  other  food  plants  in  the  spring  and  early  sum- 
mer, inasmuch  as  only  a part  of  its  cycle  of  life  has  been  determined. 

These  three  species  are  the  most  important  of  the  Texas  economic 
Anthonomi,  and  from  the  two  latter  little  may  be  expected  in  assisting 
in  the  control  of  the  boll  weevil,  altho  it  may  be  important  to  suggest 


39 


40 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


that  the  parasites  of  Anthonomus  signatus  might  attack  Anthonomus 
aeneotinctus  if  the  strawberry  and  pepper  were  grown  side  by  side. 
The  former  weevil  has  long  been  established  and  has  numerous  para- 
sites. The  latter  has  not  been  here  long  and  has  not  extended  its  foot- 
hold greatly,  neither  has  it  many  parasites.  Both  of  these  species  are 
small,  and  perhaps  not  likely  to  yield  parasites  which  would  attack 
larger  species. 

Of  the  large  species  equaling  the  boll  weevil  in  size  some  may, 
perhaps,  yield  favorable  results.  Anthonomus  fulvus  Lee.  gives  prom- 
ise in  one  way  because  it  breeds  in  the  buds  of  Callirrhoe  involucrata, 
a mallow  closely  related  to  cotton.  But  this  plant  ceases  flowering 
early  in  July,  which  would  make  transfer  of  parasites  difficult. 
The  biology  of  this  species  is  extremely  like  that  of  the  boll  weevil, 
and  it  would  appear  to  be  easier  for  parasites  to  change  from  it  to  its 
more  injurious  relative  than  from  the  two  species  mentioned  before. 
Anthonomus  squamosus  Lee.,  which  breeds  along  the  western  edge  of 
the  cotton  belt  in  the  flowers  of  Grindelia  squarrosa  nuda , is  much 
more  abundantly  parasitized  than  A.  fulvus  has  proven  to  be.  Its 
food  plant  has  a long  season,  so  that  several  generations  are  produced. 
Both  of  these  species  seal  the  egg  puncture  and  pupate  in  a cell 
formed  by  the  larval  excrement,  just  as  does  the  boll  weevil.  Both 
are  parasitized  likewise  by  Bracon  mellitor  Say,  a parasite  of  Antho- 
nomus grandis.  Eurytoma  tylodermatis  Ashm. , listed  as  a parasite  of 
Anthonomus  grandis , is  a primary  parasite  of  Lixus  musculus  Sa}r 
and  probably  also  of  Anthonomus  squamosus.  Another  species  of 
Eurytoma  was  definitely  bred  from  A.  squamosus.  Anthonomus  scu- 
tellaris  Lee.  is  known  to  breed  in  wild  plums  in  Texas.  Desmoris 
scapalis  Lee.,  a weevil  very  similar  in  habits  to  the  boll  weevil,  breeds 
in  the  flower  heads  of  Sideranthus  rubiginosus , thus  resembling  A. 
squamosus , but  differing  from  the  Anthonomi  mentioned,  in  that  it 
undoubtedly  pupates  in  the  ground.  This  species  is  very  abundant  in 
the  heart  of  the  weevil-infested  area  of  the  cotton  belt  and  occurs 
thruout  a considerable  part  of  the  summer.  Moreover,  it  is  often 
parasitized. 

Of  the  smaller  species  those  to  be  noticed  are  not  smaller  than  the 
shiallest  of  A.  grandis  and  A.  squamosus.  Anthonom  us  disjunctus  Lee. , 
like  the  latter,  breeds  in  the  flower  heads  of  Heterotheca  subaxillaris , a 
common  composite  thruout  central  Texas.  It  is  very  numerous  and 
considerably  parasitized.  Anthonomus  aeneolus  Dietz  breeds  abun- 
dantly in  the  buds  of  Solanum  rostratum , which  occurs  thruout  Texas. 
Catolaccus  incert.us  has  been  bred  as  a parasite. 

The  nature  of  the  problem  being  thus  set  forth,  it  will  be  readily 
understood  that  the  primary  requisite  is  a knowledge  of  the  breeding 
habits  of  as  many  species  of  weevils  as  possible. 


NOTES  ON  THE  BIOLOGY  OF  RELATED  WEEVILS. 


41 


The  following  notes  bear  upon  the  biology  of  certain  of  the  Texas 
weevils.  The  determinations  are  by  Messrs.  E.  A.  Schwarz,  W.  H. 
Ashmead,  D.  W.  Coquillett,  August  Busck,  and  W.  E.  Hinds,  in  those 
groups  respectively  in  which  they  are  specialists. 

ANTHONOMUS  DISJUNCTUS  Lee. 

This  species  was  found  breeding  in  large  numbers  on  Heterotheca 
subaxillarls  at  Jacksonville,  Tex.,  by  Mr.  C.  R.  Jones  and  the  writer. 
It  oviposits  in  the  bud  at  the  base  thru  the  involucre.  The  presence 
of  the  weevil  is  indicated  by  the  blackening  of  the  two  or  three  involu- 
cral  bracts  which  were  punctured.  The  larva  feeds  among  the  seed 
in  the  seed-head,  and  forms  a compact  cell  of  its  exuviae.  Here  it 
pupates  and  the  adult  emerges  from  the  dried  head. 

PARASITES. 

Three  pteromalids  were  bred  from  a few  buds  brought  in  to  the 
laboratory. 

ANTHONOMUS  FULVUS  Lee. 

Mr.  W.  W.  Yothers  has  carried  out  an  extensive  series  of  notes  on 
the  biology  of  Anthonomus  fulvus  incident  to  his  finding  the  host 
plant  of  this  species.  On  June  9 the  first  weevils  were  taken,  and 
found  to  be  very  abundant  on  the  flowers  of  the  purple  mallow, 
Callirrhoe  involucrata.  This  was,  then,  the  weevil  that  had  been 
sought  so  long — a native  insect  infesting  a close  relative  of  the  cotton, 
and  with  life  history  parallel  in  all  details  to  that  of  the  boll  weevil. 
The  questions  at  once  arose  as  to  whether  the  new  weevil  was  held  in 
check  by  parasites  which  might  be  transferred  to  the  boll  weevil, 
whether  it  had  more  than  one  host  plant,  whether  it  would  feed  on 
cotton,  and  whether  the  boll  weevil  would  feed  on  the  mallow. 

The  work  of  the  season  of  1905  answered  some  of  these  questions, 
but  not  the  one  of  primary  interest.  Only  one  parasite  was  bred, 
viz,  Bracon  mellitor , already  known  as  a primary  parasite  of  Anthono- 
mus grandis.  If  this  parasite  was  not  originally  parasitic  on  A.  grandis 
and  was  so  on  A.  fulvus  we  may  reasonably  expect  that  any  other 
primary  parasite  of  the  latter  ma}7  be  induced  to  transfer  its  energies 
against  the  former. 

The  host  plant,  Callirrhoe  involucrata , is  largely  distributed  over  the 
Mississippi  River  basin,  and  its  guest,  Anthonomus  fulvus,  is  known 
by  previous  record  to  occur  in  Kansas  and  by  observations  of  this 
laboratory  to  breed  at  Ardmore,  Ind.  T.  (C.  R.  Jones,  collector),  and 
Dallas  and  Victoria,  Tex.  Thus  it  is  highly  probable  that  the  weevil’s 
range  is  at  least  coextensive  with  the  range  of  this  host  plant. 

The  plant  is  a spring  bloomer,  thriving  in  May  and  dune  in  Texas 
and  gradually  later  toward  the  north.  According  to  the  laboratory 


42 


PAPEKS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


records,  the  weevil’s  activity  is  probably  limited  to  the  flowering  activ-  1 
ity  of  the  plant,  after  which  it  goes  into  estivation  and  hibernation. 

The  weevil  generalty  oviposits  in  the  bud,  altho  perhaps  also  in  the 
ovary.  The  egg  puncture  is  immediately  sealed,  just  as  by  Anthono-  1 
mus  grandis.  Owing  to  the  brief  period  from  bud  to  flower  the 
metamorphosis  is  comparatively  rapid.  The  only  observation  on  this  ' 
point  limited  the  pupa  stage  to  less  than  4 days.  The  egg  is  lemon- 
yellow,  elliptical,  measuring  0.875  mm.  in  breadth  and  0.484  mm.  in 
length.  It  is  placed  among  the  anthers,  generally  near  the  base  of 
the  floral  column.  Incident  to  the  act  of  oviposition  the  petals  become 
sealed  by  the  released  juices  and  are  prevented  from  fully  opening,  so  j 
that  the  developing  we’evil  is  still  protected  from  its  enemies.  Larvae  ' 
or  pupae  are  often  found  thus  in  the  sealed  flower,  and  are  sometimes 
still  in  this  part  after  it  has  dropt.  On  the  other  hand  the  larvae 
frequently  eat  into  the  ovary  and  there  construct  a pupal  cell  of  their 
excrement.  The  weevils  may  oviposit  in  the  ovary,  altho  no  definite 
record  was  obtained.  The  ovaries  are  largely  infested  by  a very 
small  weevil,  which  is  as  yet  undetermined.  After  June  9 neither 
copulation  nor  oviposition  was  observed. 

July  4 was  the  last  date  of  finding  larvae  in  the  field.  Thirty-two 
flowers  had  but  two  larvae,  and  two  showed  feeding  punctures.  On 
July  1 seven  adults  were  taken  in  the  field.  The  Callirrhoe  ceased 
blooming  about  July  10.  As  the  weevils  in  the  breeding  cages  ceased 
to  feed  on  the  flowers  early  in  July,  they  were  placed  with  a plant  in 
a large  breeding  cage  for  estivation  on  July  27.  The  Callirrhoe 
plants  were  induced  to  bloom  until  about  November  1 by  transplant- 
ing, but  the  weevils  did  not  seem  inclined  to  feed  again.  A weevil 
which  had  not  fed  for  a month  was  still  active  August  9,  and  on 
August  16  was  observed  to  feed  on  the  flowers  of  the  host  plant. 

The  weevils  normally  feed  on  the  anthers  and  on  the  surface  of  the 
petals.  They  refused  to  touch  the  foliage.  When  offered  a choice  of 
Callirrhoe  or  cotton  blooms,  they  almost  invariably  went  directty  to 
the  former.  When  given  cotton  alone  they  were  observed  to  feed  on  j 
the  pollen  and  petals  and  in  one  case  indication  of  feeding  on  the  square  j 
was  observed. 

In  habit  the  weevil  is  like  Anthonomus  grandis.  It  is  susceptible  j 
to  movement  and  when  conscious  of  a disturbance  remains  alert  on  the  ' 
edge  of  a petal.  A slight  movement  will  cause  it  to  drop  to  the  j 
ground,  where  it  is  almost  impossible  to  find  it.  It  is  a very  ready  J 
flyer  and  goes  from  plant  to  plant  in  this  manner. 

ANTHONOMUS  SQUAMOSUS  Lee. 

This  species  was  found  breeding  in  very  large  numbers  by  Mr.  C.  R. 
Jones  and  the  writer  on  Grindelia  squarrosa  nuda  at  Clarendon,  Tex.  I 
It  has  previously  been  recorded  from  the  same  plant  in  Colorado  and  1 


Bui.  63,  Part  II,  Bureau  of  Entomology,  U.  S.  Dept,  of  Agriculture. 


Plate  I. 


Work  of  Lixus  musculus  and  Orthoris  crotchii. 

Fig.  1. — Gall  ot"  Lixus  musculus  and  exit  hole  of  adult  on  stem  of  Polygonum  pcnnsylvanicum. 
Fig.  2. — Gall  of  Lixus  musculus  and  entrance  hole  (closed)  of  pyralid  caterpillar  on  stem  of 
Polygonum.  Fig.  3. — Pod  of  Mentzelia  nuda , showing  two  egg  punctures  of  Orthoris  crotchii. 
Fig.  4. — Pod  of  Mentzelia  opened,  showing  a cluster  of  Orthoris  crotchii  cells,  and  the  cocoons 
of  Tetrastichus.  Figs.  5,  6. — Interior  of  pod  of  same,  showing  several  cells  of  Orthoris  crotchii. 
Fig.  7. — An  isolated  cell  of  Orthoris  crotchii,  showing  the  manner  in  which  the  seeds  are 
eaten.  (Original.) 


NOTES  ON  THE  BIOLOGY  OF  RELATED  WEEVILS. 


43 


what  was  supposedly  the  same  species  from  Helianthus  in  Kansas.  It 
oviposits  in  the  bud  or  flower  at  the  base  thru  the  involucre.  The 
presence  of  the  weevil  is  indicated  by  the  blackening  of  the  two  or 
three  punctured  involucral  bracts.  The  larva  feeds  among  the  ovaries 
in  the  flower  head  and  forms  a compact  cell  from  its  exuviae.  This 
cell  is  the  more  compact  because  of  the  sticky  nature  of  the  flower. 
Here  it  pupates  and  matures,  the  adult  emerging  from  the  dry  seed 
head.  The  specimens  secured  differ  greatly  in  size,  color,  and  vestiture. 

PARASITES. 

Bracon  mellitor  Say  was  bred  in  large  numbers  from  the  larvae. 

Eurytoma  tylodermatis  Ashm.  was  bred  in  large  numbers  as  a pri- 
mary parasite. 

Catolaccus  sp.  One  specimen  of  this  genus  was  bred,  and  is  pre- 
sumably a primary  parasite. 

An  undetermined  noctuid  caterpillar,  which  eats  out  the  heads  of  the 
Grindelia,  destroys  all  weevils  breeding  in  the  flowers  it  attacks. 

LIXUS  MUSCULUS  Say.  (Pl.  I,  figs.  1,  2.) 

This  species  was  found  by  Mr.  C.  R.  Jones  and  the  writer  breeding 
in  considerable  numbers  in  the  stems  of  Polygonum  jpennsylvanicum 
at  Clarendon,  Tex.  It  oviposits  near  the  joints  of  the  stem,  and  the 
young  larva  as  it  feeds  causes  the  stem  to  enlarge  and  form  a gall-like 
cell.  These  galls  are  twice  the  diameter  of  the  stem  and  about  three- 
quarters  of  an  inch  long.  The  growing  weevil  fits  its  cell  tightly,  and 
consequently,  after  maturing,  it  takes  some  time  for  it  to  gain  an  exit. 
The  adultignaws  a round  hole  in  front  of  its  head  and  then  gradually 
forces  itself  out. 

PARASITES. 

Glyptomorplia  ( Bracon ) rugator  Say.  One  adult  was  bred  from  the 
weevil  and  numerous  pupae  were  found  in  the  cells.  The  pupa  is 
inclosed  in  a brown  papery  cocoon,  which  completely  fills  the  cell  and 
crowds  the  remains  of  the  Lixus  against  the  wall. 

Eurytoma  tylodermatis  Ashm.  was  bred  as  a primary  parasite. 

Neocatolaccus  tylodermse  Ashm.  was  bred  as  a primary  parasite. 
This  species  has  been  bred  also  from  boll-weevil-infested  squares. 

Cerambycobius  cyaneiceps  Ashm.  One  specimen  was  bred  from  an 
infested  stem,  and  is  probably  a Lixus  parasite. 

Eurytoma  tylodermatis  Ashm.  One  individual  bred  from  an  infested 
stem  and  probably  a parasite  of  Lixus,  tho  perhaps  hyperparasitic. 

A p3^ralid  larva  which  dwells  in  the  stems  of  this  plant  seems  to  be 
very  fond  of  this  weevil,  as  it  not  only  eats  those  which  lie  in  its  path 
but  has  been  frequently  seen  to  cut  a hole  into  the  galls  from  the  outside 


44 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


and  to  feed  on  the  inmate.  It  makes  no  choice  or  the  stage  of  the 
weevil  to  be  eaten;  larvae,  pupae,  and  adults  have  been  found  partly 
devoured. 

ORTHORIS  CROTCHII  Lee.  (PI.  I,  figs.  3-7.) 

This  species  was  found  by  Mr.  C.  R.  Jones  and  the  writer  breeding 
in  Mentzelia  nuda  at  Clarendon,  Tex.  It  oviposits  in  the  ripening- 
seed  pods,  and  the  larva  makes  its  cell  in  the  center  of  six  or  seven  of 
the  hat  transverse  seeds.  Very  often  four  or  five  weevil  cells  will 
lie  side  by  side,  occupying  a large  part  of  the  interior  of  the  pod. 
The  cells  are  made  up  of  the  exuviae  of  the  larvae.  Exit  is  secured 
thru  the  open  apex  of  the  ripe  pod. 

PARASITES. 

Microbracon  ( Bracon ) nuperiis  Cress,  was  bred  in  very  large  numbers 
as  a primary  parasite.  The  air  around  the  Mentzelia  bushes  was  thick 
with  individuals  of  this  and  the  next  species.  Several  definite  records 
of  hyperparasitism  by  Tetrastichus  were  obtained.  The  latter  con- 
struct beautiful  little  white  cocoons,  and  several  feed  on  one  host. 

Tetrastichus  sp.  A very  large  number  of  these  specimens  were  bred 
from  the  Mentzelia  pods,  and  several  very  definite  cases  of  primary 
parasitism  were  recorded. 

O 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ENTOMOLOGY  BULLETIN  No.  63,  Part  III. 

L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau. 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL  AND 
RELATED  AND  ASSOCIATED  INSECTS. 


AN  ANT  ENEMY  OF 
THE  COTTON  BOLL  WEEVIL. 

BA' 

W.  E.  HINDS, 

In  Charge  of  Cotton  Boll  Weevil  Laboratory. 


Issued  February  5,  1907. 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE 

1907. 


LETTER  OF  TRANSMITTAL. 


U.  S.  Department  of  Agriculture, 

Bureau  of  Entomology, 
Washington , D.  C.,  November  1906. 

Sir:  I submit  herewith  manuscript  of  a paper  on  an  ant  enemy  of 
the  cotton  boll  weevil,  by  Dr.  W.  E.  Hinds,  which  I recommend  for 
publication  as  Part  III  of  Bulletin  No.  63.  The  account  of  this  well-  | 
known  cotton  ant  is  of  especial  interest,  since  it  seems  to  be  a much 
more  important  enemy  of  the  cotton  boll  weevil  than  has  heretofore 
been  supposed. 

Respectfully,  L.  O.  Howard, 

Entomologist  and  Chief  of  Bureau.  I 

Hon.  James  Wilson, 

Secretary  of  Agriculture. 


ii 


CONTENTS. 


Page. 

Introduction 45 

Description 45 

An  enemy  of  the  cotton  leaf- worm  and  bollworm 46 

Its  work  as  an  enemy  of  the  cotton  boll  weevil 46 

Distribution 48 


ILLUSTRATION. 


Page. 

Fig.  7.  An  ant  enemy  of  the  cotton  boll  weevil:  Cotton  squares  showing 
emergence  bole  of  weevil  and  entrance  holes  of  Solenopsis  geminata 
var.  xyloni  for  comparison • 47 

in 


U.  S.  D.  A.,  B.  E.  Bill.  63,  Part  III. 


C.  B.  W.  L,  February 


1907. 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL  AND 
RELATED  AND  ASSOCIATED  INSECTS. 


AN  ANT  ENEMY  OF  THE  COTTON  BOLL  WEEVIL. 

( Solenopsis  geminatci,  Fab.  var.  xyloni  McC. ) 

By  W.  E.  Hinds, 

In  Charge  of  Cotton  Boll  Weevil  Laboratory . 

INTRODUCTION. 

That  native  species  of  ants  are  the  most  important  predatory  ene- 
mies of  the  boll  weevil  is  an  admitted  fact,  but  the  real  extent  of  their 
beneficial  work  has  probably  been  underestimated  rather  than  over- 
estimated. Several  species  have  been  found  attacking-  the  weevil  in 
some  of  its  stages,  but  by  far  the  most  important  one  as  yet  observed 
is  a rather  small  species  determined  by  Dr.  W.  M.  Wheeler  as 
Solenopsis  geminata  Fab.  var.  xyloni  McC.  This  ant  is  quite  variable 
in  size  and  color,  and  the  different  forms  found  in  Texas  have  been 
separated  into  several  varieties.  As  it  is  probable  that  the  food 
habits  are  similar  in  each  of  these  forms,  the  varietal  distinctions 
need  not  be  emphasized  here. 

Doctor  Wheeler  has  kindly  furnished  the  following  information: 

The  species  is  common  everywhere  in  the  warmer  parts  of  the  world,  and  is  both 
highly  carnivorous  and  highly  vegetarian;  that  is,  it  will  prey  on  any  defenseless  or 
moribund  insects,  and  stores  seeds  in  the  chambers  of  its  nest.  It  stings  very 
severely,  whence  the  name  “fire-ant”  or  “ Hormiga  brava,”  which  is  given  it  in 
Spanish  America.  The  dark  variety  you  sent  is  common  in  the  black  soil,  such  as 
one  finds  in  cotton  fields.  I have  seen  it  in  great  abundance  in  the  vicinity  of 
Austin,  Tex. 

DESCRIPTION. « 

For  the  present  purpose  this  ant  may  be  characterized  as  follows: 

There  are  two  distinct  nodes  or  scales  in  the  slender  petiole  of  the  abdomen.  All 
forms  but  the  male  have  a sting.  The  antennae  are  ten-segmented;  the  club  is 
formed  of  the  last  two  segments,  of  which  the  terminal  one  is  the  longer.  Maxillary 
and  labial  palpi  have  each  two  segments.  The  clypeus  has  two  longitudinal  ridges 
and  the  sting  is  very  large.  The  color  varies,  but  the  workers  usually  seen  are  of  a 
dark  reddish  brown,  the  color  of  the  abdomen  being  often  considerably  darker  than 
that  of  the  head  and  thorax.  Length  of  workers  from  2 to  3 mm. 

a For  illustration  of  the  species  see  Bui.  51,  Bur.  Ent.,  U.  S.  Dept.  Agric.,  fig.  8, 
p.  149. 


45 


46 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


AN  ENEMY  OF  THE  COTTON  LEAF-WORM  AND  BOLLWORM. 

This  species  has  long  been  known  as  an  important  enemy  of  the  cot- 
ton leaf-worm  ( Alabama  argillacea  Ilbn.),  what  is  probably  the  first 
notice  of  its  good  service  in  this  connection  having  been  published  in 
1847.  Since  that  time  so  many  observers  have  reported  it  as. attacking 
the  eggs,  larvae,  and  pupae  of  the  leaf-worm  that  there  can  be  no  doubt 
of  the  substantial  accuracy  of  the  conclusion  that  it  is  one  of  the  most 
important  predaceous  enemies  of  that  cotton  pest. 

While  less  study  has  naturally  been  given  to  the  relationship  of  ants 
to  the  cotton  bollworm  than  to  the  leaf-worm,  it  has  been  shown 
repeatedly  that  the  species  under  consideration  preys  upon  both  the 
eggs  and  larvae  of  the  bollworm  in  much  the  same  way  as  it  does  with 
the  leaf -worm. 

ITS  WORK  AS  AN  ENEMY  OF  THE  COTTON  BOLL  WEEVIL. 

Considering  the  important  place  that  these  ants  hold  among  the  nat- 
ural foes  of  the  two  cotton  pests  of  most  serious  importance  before 
the  advent  of  the  Mexican  cotton  boll  weevil,  it  is  not  at  all  surprizing 
to  find  it  tilling  a high  place  as  an  enemy  of  the  weevil.  For  several 
years  it  has  been  known  that  ants  frequently  attack  the  immature 
stages  of  the  weevil  in  both  squares  and  bolls,  but  observations  made  j 
during  the  season  of  1905  have  shown  that  this  native  ant  may  be — at 
least  under  favorable  conditions — a more  important  factor  in  the  I 
destruction  of  the  weevil  than  has  hitherto  been  supposed. 

During  the  experiment  which  was  being  made  to  test  the  effect  of 
direct  sunshine  in  destroying  immature  stages  of  the  weevil,  150 
squares  were  selected,  each  of  which  was  believed  to  contain  some  : 
stage  of  the  insect.  These  squares  were  divided  into  two  lots  of  75 
squares  each  and  placed  upon  the  bare  ground  in  an  exposed  spot  in  : 
the  cotton  plat  at  the  laboratory  in  Dallas,  Tex.  One  lot  was  left  dry,  , 
while  the  other  was  thoroly  wetted  to  determine  whether  the  mortality  P 
would  be  as  great  in  exposed  squares  which  were  kept  moist.  The  j 
squares  were  placed  on  the  ground  at  4.30  p.  m.,  September  5.  The 
following  morning,  while  again  wetting  the  lot  which  was  to  be  kept  j 
moist,  numerous  ants  were  noticed  running  around  and  over  the 
squares,  tho  no  sign  of  a nest  had  been  seen  near  that  spot  on  the  i 
previous  evening.  A hasty  examination  showed,  in  several  squares,  1 
holes  (fig.  7,  b,  c)  which  in  size  and  external  appearance  resembled  weevil  |' 
emergence  holes  (fig.  7,  a)  so  closely  that  at  first  the}r  were  mistaken  for 
them,  and  it  was  feared  that  the  stages  of  the  weevil  in  the  squares  were 
too  nearty  mature  to  serve  as  suitable  material  for  the  experiment 
intended.  A more  careful  examination,  however,  showed  that  the 
weevils  were  not  emerging,  but  that  the  holes  in  the  squares  were  realty 
entrance  holes  made  by  the  ants  to  enable  them  to  get  at  the  immature 
weevils  within.  As  it  was  evident  that  nearly  all  of  the  squares  had 
been  opened,  the  experiment  intended  was  abandoned  and  a complete 
examination  made  of  all  the  squares. 


AN  ANT  ENEMY  OF  THE  COTTON  BOLL  WEEVIL. 


47 


It  was  soon  found  that  the  ant- made  holes  could,  from  internal 
conditions  if  not  from  external  appearances,  be  distinguished  posi- 
tively from  those  made  by  the  weevil,  and  it  was  also  possible  to 
tell  with  considerable  certainty  whether  the  victim  was  in  the  larval  or 
the  pupal  stage,  tho  in  only  a few  cases  had  the  ants  left  any  remains 
of  their  prey.  A careful  examination  of  the  interior  of  a square 
from  which  a weevil  has  emerged  shows  invariably  a small  quantity 
of  fine  debris  removed  by  the  weevil  from  the  wall  of  the  square  in 
cutting-  its  way  out.  Besides  this,  there  is  a small  amount  of  white 
excrementitious  material,  the  final  product  of  the  transformation, 
which  is  voided  by  the  weevil  before  it  leaves  its  cell. 


Fig.  7.— An  ant  enemy  of  the  cotton  boll  weevil:  a,  cotton  square  showing  emergence  hole  of  boll 
weevil;  b,  c,  cotton  squares  showing  entrance  holes  of  Solenoj^sis  geminata  var.  xyloni.  Slightly 
enlarged  (original). 

In  cases  where  the  squares  had  been  entered  bj^  ants  and  an  imma- 
ture stage  destroyed,  neither  of  these  signs  of  adult  weevil  activity 
• could  be  found,  but  the  stage  of  the  weevil  could  in  most  cases  be  told 
from  the  presence  or  absence  of  the  larval  exuviae,  which  are  generally 
untouched  by  the  ants. 

In  the  lot  of  75  squares  kept  dry  it  was  found  that  the  ants  had 
entered  64,  destroying  44  stages  which  were  probably  larvae  and  20 
i which  were  probably  pupae.  Eleven  squares  showed  no  ant  holes. 
Of  these,  7 contained  no  weevil  stage,  3 contained  live,  unharmed 
larvae  of  a parasite  of  the  weevil  ( Bracon  mellitor  Say)  and  the 


48 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


remains  of  the  weevil  larva?  destroyed  by  them,  and  1 a dead,  moldy 
weevil  larva. 

In  the  lot  of  75  squares  kept  wet  the  ants  had  entered  73,  destroying 
50  stages  which  probably  were  larvae  and  23  probably  pupa?.  The  2 
squares  not  entered  by  the  ants  had  contained  no  stages  of  the  weevil. 
No  signs  of  parasite  destruction  could  be  found  in  this  lot  of  wet 
squares. 

A brief  summary  of  the  examination  of  these  150  squares  shows' 
that  9 of  them  did  not  contain  any  stage  of  the  weevil.  Not  one  of 
the  uninfested  squares  nor,  apparently,  an}r  one  of  those  containing  a 
parasitized  or  dead  larva  was  opened  by  the  ants.  Among  the  137 
squares  opened  by  the  ants  not  a single  weevil  stage  escaped  destruc- 
tion, tho  the  squares  had  been  on  the  ground  but  eighteen  hours. 

The  unquestionable  connection  of  these  ants  with  the  rapid  and  com- 
plete destruction  of  every  living  weevil  stage  in  150  squares  shows 
their  possible  efficacy  in  the  held  under  conditions  which  favor  their 
work.  The  ants  were  not  exceptionally  abundant  where  the  foregoing 
demonstration  occurred.  The  nearest  nest  was  under  a^otton  plant 
about  3 feet  from  the  bare  spot  where  the  squares  were  exposed. 

On  September  25  an  examination  was  made  of  300  fallen  squares 
and  small  bolls  collected  at  random  from  the  ground  in  this  plat.  It 
was  found  that  at  that  time  the  ants  had  destroyed  40  per  cent  of  all 
weevil  stages  infesting  those  squares  and  bolls.  October  6,  in  an 
examination  of  212  fallen  squares  and  small  bolls,  it  was  found  that 
the  ants  had  destroyed  35  per  cent  of  the  weevil  stages.  Observations 
made  after  November  1 indicated  that  the  ants  had  then  practically 
ceased  their  activity,  only  about  10  per  cent  of  the  weevil  stages 
having  been  destroyed.  The  ants  appear  to  be  unable  to  enter  the 
square  or  small  boll  until  after  decay  has  softened  and  weakened  the 
resistance  of  the  walls  inclosing  the  weevil. 

DISTRIBUTION. 

These  ants  nest  in  the  cotton  fields  and  appear  to  be  distributed  over 
most  if  not  all  of  the  cotton  belt.  Their  activity  is  far  greater  during 
hot  dry  weather  than  during  cold  wet  weather;  and  this  fact  may 
account  in  some  measure  for  the  effect  which  wet  weather  is  said  to 
have  in  greatly  increasing  the  numbers  and  destructiveness  of  the 
insect  pests  of  cotton." 

During  the  past  season  Solenopsis  gerninata  var.  xyloni  has  been 
taken  from  infested  cotton  fields  in  many  localities  in  Texas  and  west- 
ern Louisiana.  It  seems  to  be  perfectly  at  home  in  various  types  of 
soil,  and  is  undoubtedly  of  considerable  benefit  as  an  established  enemy 
of  the  weevil  in  practically  all  of  the  area  now  infested. 

o Bui. *51,  Bur.  Ent.,  U.  S.  Dept.  Agrie.,  pp.  137-138. 


o 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ENTOMOLOGY— BULLETIN  No.  63,  Part  IV. 

L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau. 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL  AND 
RELATED  AND  ASSOCIATED  INSECTS. 


A PREDATORY  BUG  REPORTED  AS 
AN  ENEMY  OF  THE  COTTON  BOLL  WEEVIL. 


A.  C.  MORGAN, 


Special  Field  Agent. 


Issued  February  8,  1907. 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE. 

1907. 


LETTER  OF  TRANSMITTAL. 


U.  S.  Department  of  Agriculture, 

Bureau  of  Entomology, 
Washington,  I).  C. , November  88,  1906. 

Sir:  I have  the  honor  to  transmit  herewith  a brief  manuscript,  by 
Mr.  A.  C.  Morgan  of  this  Bureau,  concerning  a predatory  bug  which 
was  reported  as  an  enemy  of  the  boll  weevil,  but  which,  upon  investi- 
gation, proves  to  be  a species  of  economic  insignificance.  In  order 
that  the  facts  learned  concerning  this  insect  may  be  put  on  record  for 
future  reference,  I recommend  the  publication  of  the  paper  as  Part  IV 
of  Bulletin  No.  63. 

Respectfully,  L.  O.  Howard, 

Entomologist  and  Chief  of  Burea  u. 

Hon.  James  Wilson, 

Secretary  of  Agriculture. 


ii 


CONTENTS. 


Page. 

Introduction 49 

Life  history 49 

Copulation 49 

Oviposition 49 

The  egg 49 

Incuba  ion 50 

Food 50 

Food  of  the  young 52 

Cannibalism 53 

Length  of  life  cycle 53 

Natural  enemies 54 

Distribution 54 

Conclusion 54 


IT  LUSTRATIONS. 


Page. 

Fig.  8.  Apiomerus  spissipes:  adult,  egg  mass,  nymph 50 

9.  Apiomerus  spissipes:  egg 50 

in 


U.  S.  D.  A.,  B.  E.  Bui.  63,  Part  IV. 


C.  B.  W.  I.,  February  8,  1907. 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL  AND 
RELATED  AND  ASSOCIATED  INSECTS. 


A PREDATORY  BUG  REPORTED  AS  AN  ENEMY  OF  THE  COTTON 

BOLL  WEEVIL. 

(Apiomerus  spissipes  Say.) a 

By  A.  C.  Morgan, 

Special  Field  Agent. 

INTRODUCTION. 

On  May  3,  1905,  the  writer  was  sent  to  Gurley,  Tex.,  to  investigate 
the  finding,  by  Mr.  Sam.  Allen,  of  that  place,  of  a bug  which  he 
reported  as  an  enemy  to  the  Mexican  cotton  boll  weevil  ( Anthonomus 
gmndis  Boh.).  Mr.  Allen  had  collected  only  one  specimen,  a nymph 
of  Apiomerus  spissipes  Say.  It  was  taken  to  Dallas-,  Tex.,  where  it 
soon  molted  and  became  adult.  Other  adults  were  afterwards  placed 
under  observation  at  Dallas  in  order  that  the  life  history  and  habits 
of  the  species  might  be  studied  to  determine  to  what  extent  it  was 
an  enemy  of  the  boll  weevil,  and  whether  or  not  it  is  likely  to  become 
of  economic  importance. 

Credit  is  due  Mr.  W.  W.  Yothers  for  valuable  notes  upon  the  life 
history  of  this  species,  especially  as  regards  its  food  habits. 

LIFE  HISTORY. 

Copulation. — May  23,  1905,  a pair  was  observed  in  copulation  in 
the  field  for  over  6 hours  at  Gurley.  Later,  at  Dallas,  a pair  was 
in  copulation  for  4 hours,  and  another  pair  for  3 hours.  During  the 
process  the  female  assumes  the  normal  position  while  the  male  clings 
to  o.ne  side  of  her,  holding  on  with  the  fore  and  hind  legs. 

Oviposition. — The  eggs  are  laid  in  masses  (fig.  8,  l)  of  40  to  60, 
tho  as  few  as  10  were  recorded  in  one  instance  and  23  in  another. 
Individual  records  are  as  follows:  3T,  41,  49,  54,  and  64.  The  usual 
place  for  oviposition  is  the  underside  of  a leaf,  near  the  top  of  the 
plant.  Lgg  masses  have  been  collected  in  this  position  from  Ambrosia 
sp.  and  Ilelianthus  sp.  The  eggs  are  placed  so  close  to  each  other, 
side  bv  side,  that  in  the  center  of  the  mass,  instead  of  being  cylindrical, 
they  are  usually  more  or  less  hexagonal. 

The  egg.—  The  egg  (fig.  9)  is  cylindrical,  finely  punctured,  and  varies 
in  color  from  a bright  yellow  when  first  deposited  to  a light  brown 

« Order  Hemiptera,  family  Reduviidre. 


49 


50 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


«i 

..  . . 

Pi 

w%lK 

■! 

Fig.  8. — Apiomerus  spissipes : a,  nymph,  5th  instar;  b,  egg  mass;  c, 
adult,  side  view;  d,  same  from  above,  a,  c,  d,  natural  size;  b, 
enlarged  (original). 


just  before  hatching.  The  collar  is  shining  white.  The  dimen- 
sions of  the  egg  are  as  follows:  Width  at  narrowest  part — just 

below  collar — 0.5  mm.; 
greatest  width,  0.64 
mm. ; length  below  col- 
lar, 1.51  mm. ; length  of 
collar,  0.26  mm.;  total 
length,  1.77  mm.  The 
width  of  the  collar  varies 
from  slight^  less  than 
the  greatest  width  of  the 
egg  to  slightly  more. 

Incubation.  ■ — Incuba- 
tion varies  slightly  in 
the  time  required  in  dif- 
ferent egg  masses. 
Thus,  in  May,  under 
conditions  exactly  the 
same,  incubation  re- 
quired 12  days  in  one 
instance  and  16  in 
another.  During  mid- 
summer 10  to  12  days  were  sufficient.  Later,  in  the  fall,  14  to  16 
days  were  required. 

FOOD. 

The  insects  preyed  upon  in  the  laboratory  embraced  the  orders 
Orthoptera,  Heraiptera,  Lepidoptera,  Diptera,  and  Hymenoptera. 
The  process  of  feeding  is  a long  one 
and  varies  with  the  size  of  the  prey.  In 
general  the  reduviids  lie  in  wait  in  an 
alert  attitude  for  the  approach  of  an 
insect  and  then  spring  upon  it,  but 
frequently  they  take  the  initiative  and  fly 
or  run  toward  an  insect.  The  insect  fed 
upon  is  not  left  until  all  the  juices  are 
sucked  from  its  body.  Sometimes  this 
takes  only  a half  hour,  at  other  times 
the  reduviid  feeds  for  one  or  two  hours. 

Boll  weevils  fed  upon  by  Apiomerus 
spissipes  are  often  as  dry  and  crush 
almost  as  easily  between  the  fingers  as 
do  pinned  specimens.  The  first  punc- 
ture by  the  beak  of  spissipes  is  gen- 
erally fatal.  In  the  case  of  boll  weevils,  upon  which  spissipes  fre- 
quently fed,  the  weevil  made  only  a few  spasmodic  movements  after 


Fig.  9.— Eggof  Apiomerus  spissipes:  A,  side 
view  of  egg;  B,  egg-cap,  side  view;  C,  top 
view  of  egg:  a,  collar;  b,  egg  cap;  c,  point 
of  junction  of  egg  cap  with  egg;  d , at- 
tachment of  egg  to  leaf.  Much  enlarged 
(original). 


A BUG  REPORTED  AS  ENEMY  OF  BOLL  WEEVIL. 


51 


the  first  insertion  of  its  captor’s  beak,  and  then  ceased  to  move.  The 
power  of  the  bite  of  this  insect  was  well  illustrated  upon  the  writer 
while  collecting  specimens.  One  adult  inserted  1 "s  bill  in  the  end  of 
the  thumb.  The  pain  at  first  was  not  so  great  as  that  from  the  sting 
of  a bee  or  wasp,  but  in  a few  moments  it  was  much  greater  than  the 
writer  had  ever  experienced  from  any  hymenopteron’s  sting.  It 
continued  unabated  for  over  an  hour,  and  the  spot  was  tender  to 
the  touch  for  two  weeks. 

Altho  locusts,  bees,  wasps,  and  an  occasional  moth  were  eaten,  Cole- 
optera  and  Diptera  were  preferred.  The  following  tables  give  the 
food  for  a number  of  days  of  a nymph  of  Apiomerus  spisszpes,  and, 
for  comparison,  the  food  of  another  reduviid  ( Sinea  diadema  Fab.): 
Food  of  nymph  of  Apiomerus  spissipes  in  third  instar. 


Pepper  weevils  ( Anthonomus  seneo- 
tinctus ) . 


Boll  weevils  ( Anthonomus  grandis). 


Date. 

Number 

added. 

Number 

killed. 

Number 

alive 

from 

previous 

day. 

Total 

number 

alive. 

Number 

added. 

Number 

killed. 

Number 

alive 

from 

previous 

day. 

Total 

number 

alive. 

October  16 

3 

3 

1 

0 

1 

17 

5 

3 

0 

5 

0 

0 

1 

1 

19 

7 

5 

• 0 

7 

0 

0 

1 

1 

20 

5 

5 

2 

5 

0 

0 

1 

1 

21 

7 

3 

1 

8 

0 

0 

l 

1 

23 

20 

7 

1 

21 

. 0 

0 

1 

1 

24 

0 

11 

9 

10 

0 

0 

1 

1 

25 

0 

4 

5 

5 

0 

0 

1 

1 

26 

0 

2 

3 

3 

0 

0 

1 

1 

28 

5 

3 

0 

5 

5 

0 

1 

6 

30 

0 

0 

5 

5 

0 

2 

4 

4 

November  2 

0 

2 

3 

3 

0 

1 

3 

3 

4 

0 

1 

2 

2 

0 

0 

3 

3 

6 

5 

2 

0 

5 

0 

0 

3 

3 

8 

0 

2 

3 

3 

0 

0 

3 

3 

Total 

50 

3 



The  nymph  did  not  feed  after  November  8.  On  December  1 it  was 
placed  in  a cool  room  for  hibernation,  but  must  have  died  shortly 
afterwards,  for  on  January  25,  1906,  it  was  found  dead  and  shrunken. 


Food  of  an  adult  Sinea  diadema.a 


Date. 

Pepper  weevils  ( Anthonomus  seneo- 
tinctus). 

Boll  weevils  ( Anthonomus  grandis). 

Number 

added. 

Number 

killed. 

Number 
alive 
from  pre- 
vious 
day. 

Total 

number 

alive. 

Number 

added. 

Number 

killed. 

Number 
alive 
from  pre- 
vious 
day. 

Total 

number 

alive. 

October  16 

3 

3 

* 

17 

5 

3 

0 

5 

19 

7 

5 

0 

20 

5 

5 

2 

1 

21... 

5 

2 

0 

X 

23 

14 

4 

1 

15 

| 

24. . . 

9 

11 

4 

13 

25 

11 

12 

1 

12 

26 

0 

8 

4 

5 

1 

1 

28 

5 j 

3 

1 

6 

5 

1 

0 

5 

30 

1 

1 

5 

6 

4 

4 

1 

5 

November  2 

2 

3 

3 

5 

3 

4 

1 

4 

4 

0 

2 

3 

2 

0 

1 

3 

3 

6 

0 

2 

3 

3 

0 

2 

1 

1 

Total . . . 

61 

1 

12 

1 y__ 

a The  specimen  died  November  10. 


52 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


It  should  be  noted  in  these  tables  that  while  the  nymph  of  Apiomerus  x 
spissipes  killed  50  pepper  weevils,  and  Sinea  diadem  a 61  during  the 
same  period,  yet  spissipes  killed  only  3 boll  weevils,  while  Sinea  killed 
12.  These  results  indicate  that  little  benefit  can  be  expected  from 
spissipes  in  the  early  stages.  The  boll  weevil  is  too  large  for  the 
nymphs  to  capture  easily,  hence  the  choice  of  the  smaller,  pepper 
weevils.  It  would  appear  also  that  a boll  weevil  diet  is  not  a perfect  j 
one,  for  in  the  experiments  with  boll  weevils  as  food  for  adult  spissipes  \ 
all  died  in  a short  time.  One  adult  ate  27  weevils  in  thirteen  days, 
but  died  on  the  fourteenth  day.  Other  experiments  gave  similar 
results.  The  table  shows  also  that  Sinea  does  not  prefer  a diet  of 
boll  weevils.  It  ate  only  20  per  cent  as  many  boll  weevils  as  pepper 
weevils,  altho  active  enough  and  strong  enough  to  capture  and  kill 
them  easily. 

An  adult  Apiomerus  spissipes , under  observation  from  June  1 to 
July  3,  ate  2 flies,  22  ladybirds,  1 bee,  and  1 specimen  of  the  twelve- 
spotted  cucumber  beetle  ( Diabrotica  12-punctaia  Oliv.),  but  died*  on 
July  6.  Another  adult,  under  observation  from  June  10  to  21,  when 
it  died,  ate  I).  12-punctata  and  a few  ladybirds,  but  refused  the  potato 
beetle  ( Leptinotarsa  deeemlineata  Say)  and  its  larvae  and  the  sharp- 
shooter ( Ilomalodisea  triquetra  Fab.). 

Other  adults  throve  for  a time  on  house  flies,  but,  like  those  fed  j 
upon  weevils,  they  could  not  be  kept  alive.  Neither  did  any  combi-  j 
nation  of  the  above  foods  produce  any  better  results. 

Food  of  the  young. — The  impossibility  of  keeping  the  young  alive 
thru  more  than  two  or  three  instars  leads  to  the  conclusion  that 
proper  food  was  not  supplied  them.  On  June  10  several  specimens 
of  Apiomerus  spissipes  hatched  and  were  placed  in  a cage  and  supplied  j 
with  cotton  aphides  {Aphis  gossypii  Glov.)  in  abundance.  Altho  fresh 
food  was  supplied  daily,  spissipes  fed  very  rarely,  and  on  July  3 the 
experiment  was  terminated  bjT  the  death  of  the  last  of  the  nymphs. 
Other  experiments  w ith  the  cotton  aphis  resulted  as  in  the  preceding.  J 
October  3 a nymph  nearing  the  third  instar  was  fed  upon  nymphs  of  I 
Pentatoma  ligata.  It  ate  3 nymphs  on  the  3d  and  4th,  but  died  on  1 
the  5th.  A combination  of  ligata  nymphs  and  cotton  aphides  failed  I 
to  keep  another  spissipes  alive  more  than  a few  days.  On  September  6,  I 
3 specimens  of  spissipes  which  had  just  hatched  were  isolated  in  a jar  I 
containing  the  egg  mass  from  which  they  came.  On  September  8 all  i 
were  dead.  This  experiment  was  made  to  determine  whether  the  egg  I 
mass  furnishes  food  for  the  first  instar,  as  is  the  case  with  some  penta-  1 
tomids.  From  this  experiment,  and  a subsequent  one  which  gave  the  J 
same  results,  it  is  evident  that  no  food  is  obtained  from  the  egg  mass.  ;l 

The  best  results  were  obtained  by  breaking  open  heads  of  Ambrosia  jj 
in  bloom  and  letting  the  Apiomerus  spissipes  nymphs  select  food  from  ; 
the  insects  frequenting  this  flower.  Among  the  insects  found  in  Ambro-  I 


A BUG  REPORTED  AS  ENEMY  OF  BOLL  WEEVIL. 


53 


sia  flowers  spissipes  fed  upon  Tripldeps  insidiosus , a species  of  the 
weevil  genus  Apion,  many  thrips,  and  larvae  and  pupae  of  a cecidomyiid 
gall-maker. 

Cannibalism. — Cannibalism  occurs  in  this  species,  but  is  not  com- 
monly indulged  in.  On  October  3 three  specimens  of  Apiomerus spis- 
sipes that  had  not  fed  since  hatching  were  put  in  each  of  four  pill 
boxes,  without  food.  The  first  death  occurred  October  7,  the  last 
October  9.  No  instances  of  cannibalism  occurred.  Other  experi- 
ments with  newty  hatched  unfed  nymphs  gave  the  same  result — no 
cannibalism.  October  1 twenty-two  specimens  hatched  and  were  fed 
upon  insects  found  in  heads  of  Helianthus.  October  7 two  nymphs 
were  observed  eating  a third,  and  again  on  October  9,  10,  and  12  the 
same  observation  was  recorded.  Other  instances  must  have  occurred 
in  the  intervals  between  observations,  which  would  account  for  the 
death  of  individuals  not  apparently  weak  or  diseased.  It  is  evident, 
therefore,  that  the  species  is  cannibalistic,  but  it  is  apparent  that  the 
first  food  must  be  obtained  more  easily  than  it  could  be  by  a contest 
with  one  of  its  kind  of  equal  age  and  strength.  In  nature,  however, 
where  each  individual  goes  upon  a separate  quest  for  food,  it  is  very 
unlikely  that  cannibalism  is  a serious  menace  to  the  species. 

LENGTH  OF  LIFE  CYCLE. 

Owing  to  the  abnormal  conditions  in  the  laboratory,  which  made  it 
very  difficult  to  keep  either  3^oung  or  old  spissipes  alive,  the  length  of 
the  instars  could  not  be  gaged  with  certainty.  The  time  between 
copulation  and  oviposition  varied  from  4 to  7 daj^s.  Incubation 
required  10  to  16  days,  according  to  season.  The  third  molt  in  one 
instance  occurred  12  days  after  the  second,  yet  specimens  have  lived 
more  than  a month  after  the  second  molt  without  molting.  The 
absences  of  the  writer  from  the  laboratory  for  a period  of  weeks  at 
times  destroyed  the  continuit}^  of  the  experiment,  and  made  it  impos- 
sible to  follow  the  life  history  as  closely  as  was  desired.  However, 
there  can  not  be  more  than  a fragment  of  the  second  generation  in  a 
single  season.  Proper  and  improper  food  supply  was  undoubtedly  the 
cause  of  the  great  variation  in  the  length  of  instars  noted  above.  In 
nature  the  same  conditions  of  food  supplj*  undoubtedly  exist,  thus 
making  a difference  of  months  in  the  maturity  of  individuals  hatched 
from  the  same  egg  mass.  Observations  in  the  field  bear  out  this 
conclusion. 

At  no  time  during  the  year  of  1905  could  the  young  be  found  in  any 
numbers.  Altho  adults  were  frequently  observed  in  copulation  in 
June  and  July  at  Gurley,  later  observations  failed  to  disclose  more 
than  a few  young.  It  is  reasonable  to  suppose  that  among*  the  surviv- 
ors that  finally  reached  maturity  some  encounter  almost  perfect  con- 


54 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


ditions  as  regards  food,  while  others  are  barely  able  to  exist,  thus 
lengthening  the  instars  and  delaying  maturity  and  greatly  increasing 
the  length  of  the  life  cycle. 

NATURAL  ENEMIES. 

Only  one  natural  enemy  was  recorded  during  our  observations  upon 
this  species.  This  was  a proctotrypid  egg  parasite,  which  Doctor  Ash- 
mead  pronounced  a new  species  of  the  genus  Hadronotus  Forst.  Only 
one  egg  mass  was  collected  from  the  field.  Of  these  eggs  12  per  cent 
were  parasitized. 

DISTRIBUTION. 

Say,  in  describing  this  species,  reports  it  as  being  very  abundant  in 
Arkansas.  Stal,  in  his  Enumeratio  Hemipterorum,  reports  it  from 
Mexico  and  Texas.  In  the  Proceedings  of  the  Iowa  Academy  of 
Sciences  Osborn  reports  it  from  Albuquerque,  N.  Mex.  In  1905  it 
was  collected  in  Texas  at  San  Antonio  and  Cotulla  by  J.  C.  Crawford, 
at  Handley  b}r  J.  C.  Crawford  and  W.  D.  Pierce,  at  Rosser  by  C.  R. 
Jones  and  F.  C.  Bishopp,  and  at  Gurley  and  Dallas  by  the  writer. 
Pittier  reports  it  also  from  Cruz  de  Guanacaste,  Costa  Rica,  in  Inver- 
tebrados  de  Costa  Rica. 

CONCLUSION. 

Altho  the  experiments  upon  Apiomerus  spissipes  were  conducted  in 
the  laboratoiy  under  conditions  more  or  less  unfavorable  to  the  species, 
yet  enough  has  been  learned  of  its  food  habits  to  class  it  as  a species 
of  doubtful  economic  value,  if  not  one  of  positive  injury.  Also,  its 
scarcit}^  in  cotton  fields,  even  tho  abundant  upon  the  borders,  argues 
unfavorably.  Only  occasionally  have  specimens  been  observed  upon 
cotton  plants,  and  in  the  instances  when  these  were  observed  feeding 
it  was  always  upon  ladybirds.  Again,  in  midsummer,  when  weevils 
were  most  numerous,  spissipes  could  not  be  found  either  in  the  cotton 
fields  or  near  their  borders. 

The  only  injurious  insects  fed  upon  were  the  boll  weevil  ( Anthono - 
mus  grandis ),  the  pepper  weevil  (A.  asneotinctus),  the  twelve-spotted 
cucumber  beetle  ( Diabrotiea  1% -punctata) , and  a few  house  flies.  This 
was  in  laboratory  experiments.  It  is  doubtful  if  any  of  these  are  fed 
upon  more  than  occasionally  in  the  field,  for  not  a single  instance  has 
been  recorded. 

Lastly,  the  great  mortality  of  the  young  and  consequent  paucity  of 
adults,  the  unspecialized  food  habits,  the  failure  to  feed  to  any  appre- 
ciable extent  upon  harmful  insects,  and  the  practical  disappearance 
of  the  species  from  the  vicinity  of  cultivated  fields  during  a part  of 
the  summer  would  unquestionably  place  Apiomerus  spissipes  among 
insects  of  economic  insignificance. 


O 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ENTOMOLOGY  BULLETIN  NO.  63,  Part  V. 

L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau 


PAPERS  ON 
RELATED 


COTTON  ROLL  WEEVIL  AND 
VNR  ASSOCIATED  INSECTS. 


NOTES  ON  THE 


WEEVIL 


BY 

F.  C.  PRATT, 

Assistant. 


Issued  February  9,  1907. 


WASHINGTON: 

GOVE  It  N M R N T V R INTIN  G O F PICE. 

LOOT. 


LETTER  OF  TRANSMITTAL. 


U.  S.  Department  of  Agriculture, 

Bureau  of  Entomology, 
Washington , I).  C. . November  30,  1906. 

Sip:  I have  the  honor  to  transmit  herewith  for  publication  as  Part 
V of  Bulletin  No.  63,  a brief  paper,  by  Mr.  F.  C.  Pratt  of  this  Bureau, 
cm  the  pepper  weevil,  an  insect  which  has  proven  very  destructive  to 
different  varieties  of  peppers  in  certain  localities  in  Texas  and  which, 
owing  to  a similarity  in  appearance  to  the  boll  weevil,  has  in  some 
cases  been  confused  with  that  insect. 

Respectfully,  L.  O.  Howtard, 

Entomologist  and  Chief  of  Bureau. 

Hon.  James  Wilson, 

Secretary  of  Agriculture. 


ji 


CONTENTS. 


Page. 

Occurrence  in  Texas - 55 

Origin ------ - - 55 

Food  plants - 56 

Natural  enemies - 56 

Proliferation 57 

Remedies 58 


ILLUSTRATIONS. 


PLATES. 

Page. 

Plate  II.  Work  of  the  pepper  weevil  {Anthonomus  xneotinctus)..  Fig.  1. — 
Emergence  holes  of  adult  in  chilli  pepper.  Fig.  2. — Full  grown  larvae  in 
situ  in  chilli  pepper.  Fig.  3. — Pupae  in  cells  in  chilli  pepper.  Fig.  4.  — 
Undeveloped  bell  pepper  pod,  showing  numerous  egg  and  feeding  punc- 
tures. Figs.  5,  6. — Malformed  bell  pepper  pods,  caused  by  egg  punctures.  56 

TEXT  FIGURE. 

Fig.  10.  Tiie  pepper  weevil  (Anthonomus  seneotinctus  : adult 56 

in 


p 


U.  s.  D.  A.,  B.  E.  Bui.  t>3,  Part  V. 


C.  B.  W.  I.,  February  0.  1007. 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL  AND 
RELATED  AND  ASSOCIATED  INSECTS. 


NOTES  ON  THE  PEPPER  WEEVIL. 

( Anthonomus  seneotinctus  Champ.) 

By  F.  C.  Pratt,  Assistant. 

OCCURRENCE  IN  TEXAS. 

In  a previous  bulletin a Mr.  C.  M.  Walker  gives  an  account  of  the 
pepper  weevil,  which  had  been  injuring  peppers  in  Texas.  Investiga- 
tion during  the  fall  of  1905  resulted  in  proving  the  disappearance  of 
this  insect  at  Boerne,  Tex.,  where  it  was  first  reported.  Diligent 
search  in  October  and  November  by  the  writer,  who  was  assisted  by 
Mr.  L.  Lamm,  failed  to  show  the  existence  of  the  weevils  at  that 
place,  altho  peppers  had  been  grown  as  extensively  as  before. 

At  San  Antonio,  Tex.,  many  truckers  had  given  up  the  growing  of 
peppers  on  account  of  their  experience  the  year  previous,  and  on  one 
patch  at  Collins  Gardens  fully  80  per  cent  of  the  pods  were  attacked, 
and  several  bushels  of  chilli  and  sweet  peppers  were  shipped  from 
there  to  Dallas  for  observation. 

Several  places,  Floresville,  Seguin,  and  New  Braunfels,  in  the 
vicinity  of  San  Antonio,  were  visited  to  ascertain  the  extent  of  the 
infested  territory,  but  without  success.  Corpus  Christ!  also  was  vis- 
ited, but  no  injury  was  noticed  and  no  reports  were  obtained  concern- 
ing the  weevils. 

Mr.  J.  C.  Crawford  reported  the  presence  of  the  weevil  about  8 
miles  south  of  San  Antonio,  the  grower  having  claimed  to  have  noticed 
this  insect  for  several  years.  At  Cotulla,  Tex.,  Mr.  Henry  Caley 
reported  slight  injury  at  one  of  his  truck  farms  near  that  place, 
altho  the  insect  was  not  seen  by  the  writer. 

ORIGIN. 

That  this  insect  (adult,  fig.  10)  has  been  introduced  into  the  United 
States  from  Mexico  in  recent  years,  there  is  no  doubt,  the  exact  date 
at  this  time  being  undeterminable.  Inquiries  at  San  Antonio  com- 
mission houses  elicited  the  information  that  peppers  were  shipped 
from  Laredo,  Artesia,  and  Cotulla.  As  a matter  of  fact,  few  peppers 
are  raised  at  these  places,  the  principal  crop  being  onions.  Mr.  Cale}7, 
at  Cotulla,  denied  ever  shipping  peppers  and  was  very  skeptical  about 


55 


a Bui.  54,  Bur.  Ent.,  U.  S.  Dept.  Agrie.,  pp.  43-48,  1905. 


56 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


any  having-  been  shipped  from  there  at  any^  time.  Further  information 
showed  that  peppers  were  bought  up  in  carload  lots  in  Mexico  and 

shipped  to  the  United  States  and  without  much 
doubt  rebilled  from  the  localities  mentioned 
to  give  an  impression  that  these  peppers  were 
home  grown.  Dr.  A.  W.  Morrill  reported 
that  a large  number  of  peppers  were  shipped 
annually  to  the  United  States  from  the  dis- 
tricts of  Zacatecas  and  San  Luis  Fotosi, 
Mexico,  and  he  had  collected  the  weevil  at 
Tlahualilo,  Durango,  Mexico. 

FOOD  PLANTS. 

fig.  io.— repper  weevil  (Anthou-  js  evident  that  the  weevil  does  not  breed 

omus  seneotinctus ):  Adult,  . 

Much  enlarged  (after  Hunter  in  the  wild  or  bird  pepper,  for  these  plants 
and  Hinds).  were  examined  thoroly  at  all  the  points  visited 

as  well  as  at  Victoria,  Tex.  The  bell  or  sweet  pepper  (PI.  II,  figs. 
4-6),  chilli  (PI.  II,  figs.  1-3),  and  tabasco  peppers  of  several  varieties 
are  always  affected  wherever  the  weevil  occurs. 


NATURAL  ENEMIES. 

As  in  the  case  of  the  boll  weevil  ( Anthonomus  grandis  Boh.),  altho 
a few  parasites  were  reared,  these  did  not  occur  in  sufficient  numbers 
to  keep  the  insect  in  check.  Mr.  J.  C.  Crawford  has  identified  the 
parasitic  species  as  Braconmellitor  Say,  and  Catolaccus  incertus  Ashm. 
A small  anti  Solenopsis  geminata  Fab.,fl  was  noticed  to  be  actively 
engaged  in  removing  larvae  and  pupae  from  the  pods  which  had 
weevil  exit  holes  in  them,  but  in  no  case  did  the  ants  make  an  entrance 
themselves. 

In  the  parasite  breeding  cages  thousands  of  small  mites  were 
observed  by  Mr.  W.  W.  Yothers,  who  reported  that  their  presence  in 
no  way  incommoded  the  weevils. 

To  determine  the  average  number  of  weevils  that  may  infest  the 
chilli  peppers,  several  experiments  were  tried,  with  the  following 
results: 


Experiment 

No. 

Number  of 
pods. 

Number  of 

weevils  Period  covered, 

emerged. 

1 1. 

80 

86  Oct.  18-Nov.  4. 

; 2 

230 

156  Do. 

, 3 

200 

143  Oct.  18-Nov.  11. 

4 

100 

123  Oct.  18-Oct.  31. 

Total  . . 

010 

508 

Thus  it  will  be  noticed  that  an  average  of  nearly  one  adult  to  each 
pod  was  bred. 


"See  Bui.  63,  Pt.  III,  Bur.  Ent.,  U.  S.  Dept.  Agric.  An  Ant  Enemy  of  the  Cot- 
ton Boll  Weevil.  By  W.  E.  Hinds. 


Bui.  63,  Part  V,  Bureau  of  Entomology,  U.  S.  Dept,  of  Agriculture. 


Plate  II. 


Work  of  the  Pepper  Weevil  'Anthonomus  /eneotinctus  Champ). 

Fig.  1 — Emergence  holes  of  adult  in  chilli  pepper.  Fig.  2. — Full-grown  larva  in  situ  in  chilli 
pepper.  Fig.  3.-— Pupse  in  cells  in  chilli  pepper.  Fig.  4.— Undeveloped  bell  pepper  pod, 
showing  numerous  egg  and  feeding  punctures.  Figs.  5,  6. — Malformed  bell  pepper  pods, 
caused  by  egg  punctures.  Figs.  1-3  three  times  natural  size;  fig.  4 twice  natural  size:  figs. 
5,  6 one-half  natural  size.  (Original.) 


LIBRARY 

UNlVtRSlTY  Of  ILLINOIS 


URBAN* 


NOTES  ON  THE  PEPPER  WEEVIL. 


57 


The  maximum  numbers  of  individuals  found  in  two  pods  were  as 
follows: 


Pod. 

Adults. 

Pupae. 

Larvae. 

Total. 

1... 

2 

5 

2 

9 

2... 

5 

6 

11 

Many  pods  showed  six  egg  punctures,  from  which  live  larvae,  in 
one  instance,  developed.  It  was  also  noticed  that  in  nearly  every 
case  where  egg  insertion  was  made  beyond  the  middle  of  the  pod  the 
larva  was  to  be  found  slightly  back  of  the  puncture,  but  where  the 
egg  was  deposited  between  the  stem  and  middle  of  the  pod  the  larva 
was  located  immediately  underneath.  The  average  number  of  egg 
punctures  to  a pod  proved  to  be  about  two  and  one-third. 

PROLIFERATION. « 

Proliferation  was  noticed  in  pods  purchased  in  market  at  San 
Antonio,  Tex.,  October  6, 1905,  and  the  following  two  series  of  experi- 
ments were  conducted  by  Dr.  W.  E.  Hinds  and  Mr.  W.  W.  Yothers: 


Experiments  to  determine  the  effects  on  the, pepper  weevil  of  proliferation  in  the  pepper  pods. 

FIRSTr  SEIZES. 


Oct.  14.. 

12 

11 

91.7 

0 

13 

10 

9 

6 

1 

0 

1 

5.0 

1 

8.3 

0 

0 

0 

0 

0 

0 

3 45 

Do... 

120 

111 

92.5 

0 

125 

102 

19 

34 

1 

1 

0 

0.7 

9 

7.51 

2 

o! 

o 

0 

0 

0 

( c ) (c) 

Oct.  31.. 

21 

21 

100.0 

1 

55 

34 

10 

1 

1 

0 

0 

0.0 

0 

0 

0 

0 

0 

1 

0 

0 

0 

155'  9 

153 

143 

93.5 

1 

193 

146 

38 

4! 

3 

1 

1 

1.2 

10 

6. 5 

2 

0 

0 

“ o' 

°i 

0 

a See  also  Bui.  59,  Bur.  Ent.,  U.  S.  Dept.  Agric.,  p.  38,  1906. 

6 This  is  a record  of  the  proliferated  areas  on  inside  of  pods  and  is  a minimum.— W.  E.  H. 
f Not  recorded. 


58 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


REMEDIES. 

In  addition  to  the  usual  gathering  and  destrojdng  of  fallen  pepper 
pods,  cultural  experiments  were  conducted  in  the'following  manner: 
Some  pods  were  buried  in  boxes  under  1,  2,  and  3 inches  of  soil 
respectively,  keeping  one  series  dry  and  the  other  moist — conditions 
which  would  result  necessarily  from  irrigation.  In  the  former  series 
the  pods  dried  up  and  in  the  latter  the  pods  rotted. 

Experiments  to  determine  the  effect  upon  the  pepper  weevil  of  covering  fallen  inf  ested  pods 

with  soil. 


Num- 
ber of 
pods. 

Number 
of  punc- 
tures. 

Depth 
of  soil. 

Condi- 
tion  of 
soil. 

Period  covered. 

Number  of 
weevils 
emerging 
Oct. 19-Nov. 4. 

Number  of 
weevils 
found  dead 
in  soil 
Nov.  17. 

25 

62 

Inches. 

1 

Wet  .... 

Oct.  19-Nov.  14  . . . 

i 1 adult;  1 

6 adults. 

25 

61 

1 ' 

Dry 

1 do 

parasite. 
9 adults  _ 

12  adults. 

25 

56 

2 

Wet  .... 

do 

4 adults«  . . . 

1 adult. 

25 

60 

9 

Dry 

do 

1 3 adults. . . 

5 adults. 

50 

115 

3 

do  . . . 

j 15  adults 

1 

14  adults. 

a Three  of  these  weevils  died  as  soon  as  they  came  thru  the  soil. 


Thus  it  will  be  readily  seen  that  the  covering  of  the  fallen  pods  every 
two  to  three  weeks  with  from  1 to  3 inches  of  soil  would  be  advan- 
tageous. This  could  be  arranged  by  bedding  high  and  then  lowering 
the  soil.  Where  irrigation  is  practised  the  decay  of  the  pods  is  greatly 
hastened,  thus  depriving  the  larvte  of  this  food  supply.  It  is  only  fair 
to  state  that  at  the  time  the  pods  in  these  experiments  were  buried 
most  of  the  larvae  were  nearly  full  fed,  consequently  a larger  number 
came  to  maturity  than  would  have  been  the  case  had  burial  occurred 
while  the  larvae  were  small.  Two  other  experiments  were  conducted 
by  Mr.  W.  W.  Yothers  in  large  cages  in  the  open,  with  the  following 
results: 


Experiments  to  determine  the  effect  upon  the  pepper  weevil  of  covering  fallen  infested  pods 

with  soil. 


Number 
of  pods. 

Depth  of 
soil. 

Condition 
of  soil,  i 

Date  of 
exami- 
nation. 

Nu“,bcr  Number  of 
weevils  weevils  dead 
enmr^red.j  n 80  Nov‘  »*• 

Inches. 

500 

3 

Dry« 

Oct.  20 

64  ! None  found. 

450 

2 

Drv« 1 

Oct.  28 

• 50  1 Do. 

" Heavy  rains  October  24  and  November  10. 


October  31  about  200  of  the  last-mentioned  lot  of  pods  wrere  examined 
and  found  to  contain  73  living  and  0 dead  stages;  of  this  number  47 
weir  pupae  and  15  were  larva*.  The  latter  necessarily  would  have 
starved,  owing  to  tin*  rapid' decay  of  the  buried  pods. 


O 


U.  S.  DEPARTMENT  OF  AGRICULTURE 
BUREAU  OF  ENTOMOLOGY— BULLETIN  NO.  63,  PART  VI. 

L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau. 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL  AND 
RELATED  AND  ASSOCIATED  INSECTS. 


THE  STRAWBERRY  WEEVIL 
IN  THE  SOUTH-CENTRAL  STATES  IN  1905. 

BY 

A.  W.  MORRILL, 

Special  Field  Agent. 


Issued  January  22,  1007. 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE. 

1907. 


LETTER  OF  TRANSMITTAL 


U.  S.  Department  of  Agriculture, 

Bureau  of  Entomology, 
Washington , D.  (7.,  December  i,  1906. 

Sir:  I have  the  honor  to  transmit  herewith  a brief  report  on  the 
status  of  the  strawberry  weevil  in  the  south-central  States  in  1905,  by 
Dr.  A.  W.  Morrill,  special  field  agent  in  this  Bureau.  As  this  straw- 
berry pest  is  related  to  the  boll  weevil  and  is  extensively  parasitized 
there  is  a possibility  that  some  one  or  more  of  its  parasites  ma}^  be 
induced  to  attack  the  boll  weevil.  Its  greater  or  less  abundance  in  or 
near  the  region  infested  by  the  boll  weevil  is  therefore  a matter  of 
importance.  I recommend  the  publication  of  the  report  as  Bulletin 
No.  63,  Part  VI,  of  this  Bureau. 

Respectful  I}-,  L.  O.  Howard, 

Entomologist  and  Chief  of  Bureau. 

lion,  el ames  Wilson, 

Secretary  of  Agriculture. 


ii 


CONTENTS. 


Page. 

The  strawberry  weevil  in  Texas 59 

The  strawberry  weevil  in  Louisiana 60 

The  strawberry  weevil  in  Arkansas 61 

Varieties  of  strawberries  grown 62 


in 


U.  S.  D.  A.,  B.  E.  Bui.  63,  Part  VI. 


C.  B.  W.  I.,  January  22,  1907. 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL  AND 
RELATED  AND  ASSOCIATED  INSECTS. 


THE  STRAWBERRY  WEEVIL  IN  THE  SOUTH-CENTRAL  STATES 

IN  1905. 

( Anthonornus  signatus  Say. ) 

By  A.  W.  Morrill, 

Special  Field  Agent. 

For  some  time  the  Bureau  of  Entomology  has  been  experimenting 
along  the  line  of  inducing  parasites  of  related  native  species  of 
weevils  to  prey  upon  the  cotton  boll  weevil  ( Antlionomus  grandis 
Boh.).  One  of  the  commonest  and  most  parasitized  of  such  weevils  is 
the  strawberry  weevil  (. Antlionomus  signatus  Say).  It  was  conse- 
quently important  to  ascertain  whether  this  insect  occurred  in  or  near 
the  infested  regions  of  Texas  and  Louisiana  ,and  to  what  extent  it  was 
controlled  by  parasites. 

In  connection  with  this  work,  during  the  month  of  April,  1905, 
advantage  was  taken  of  an  opportunity  to  observe  the  occurrence  and 
injury  of  the  strawberry  weevil  in  the  leading  strawberry -producing 
sections  of  Texas,  Louisiana,  and  Arkansas.  Examinations  were 
made  in  all  cases  in  the  blooming  season  when  the  insects  would,  if 
present,  occur  in  their  greatest  abundance.  In  consideration  of  the 
destructiveness  of  this  species  in  the  strawberry  fields  of  Maryland 
and  North  Carolina  during  the  past  few  years,  the  data  concerning  its 
occurrence  and  nonoccurrence  in  the  important  strawberry-growing 
sections  of  other  States  are  deemed  of  sufficient  importance  to  be 
recorded. 

THE  STRAWBERRY  WEEVIL  IN  TEXAS. 

According  to  the  latest  available  statistics  (1899), a more  than  four- 
fifths  of  the  strawberries  produced  in  the  State  of  Texas  are  grown  in 
two  limited  areas  comprizing  three  counties.  Of  these  sections  the 

« Twelfth  Census  of  the  United  States,  1900. 


59 


60 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


one  ranking  first  in  importance  includes  Brazoria  and  Galveston  coun- 
ties— two  adjoining  coast  counties  near  the  southeastern  corner  of  the 
State.  In  this  section  examinations  were  made  on  April  7 and  8 at 
Alvin  and  Galvestofi,  respectively,  but  without  finding  any  indications 
of  the  presence  of  the  strawberry  weevil.  The  second  largest  straw- 
berry-growing section  of  Texas  is  included  in  Smith  County,  near  the 
northeastern  corner  of  the  State.  An  examination  was  made  at  Tyler, 
near  the  center  of  this  section,  on  April  13,  and  again  on  April  28. 
On  the  first  of  these  dates  a single  adult  specimen  was  taken,  and  on 
the  second  occasion  two  adult  specimens.  In  a total  of  about  three 
hours  spent  near  Tyler  in  fields  of  strawberries,  blackberries,  and 
dewberries,  searching  for  these  weevils  and  for  evidence  of  their 
work,  only  the  three  adults  and  less  than  fifty  injured  buds  were  found. 

The  only  published  record  known  to  the  writer  of  the  strawberry 
weevil’s  occurrence  in  Texas  was  by  Dr.  F.  H.  Chittenden, a who  reported 
injury  by  this  species,  in  1897,  to  blackberries  and  dewberries  near 
Denison,  in  Grayson  County,  in  the  north-central  section  of  the  State. 
The  fruit  farms  of  the  two  correspondents  who  reported  serious  losses 
in  that  year  were  visited  by  the  writer  on  April  21, 1905,  and  examina- 
tions made  in  fields  of  strawberries,  blackberries,  and  dewberries.  One 
of  the  owners  reported  that  the  weevils  had  been  scarcely  noticeable 
since  April,  1897,  when  they  were  very  destructive  and  so  abundant 
that  on  sunshiny  days  they  seemed  to  fairly  swarm  on  the  foliage  of  the 
food  plants.  This  encouraging  report  concerning  its  scarcity  in  recent 
years  gives  ground  for  the  hope  that  conditions  in  northern  Texas  will 
as  a rule  be  unfavorable  for  this  pest,  altho  a certain  degree  of  inter- 
mittence  in  abundance  during  a series  of  years  has  been  generally 
observed  in  other  localities. 

THE  STRAWBERRY  WEEVIL  IN  LOUISIANA. 

In  1899,  as  shown  by  the  Census  report, b 90  per  cent  of  the  straw- 
berries produced  in  this  State  were  grown  in  Tangipahoa  Parish. 
This  parish  is  located  a short  distance  northwest  of  New  Orleans. 
Hammond,  one  of  the  two  leading  shipping  points  in  the  parish,  was 
visited  on  April  11.  Examinations  in  strawberry  fields  and  of  wild 
blackberry  bushes  along  the  roadsides,  in  a downpour  of  rain,  resulted 
in  finding  no  evidence  of  the  presence  of  the  strawberry  weevil  neai*  this 
place.  As  the  day  was  so  far  from  an  ideal  one  for  tinding  adults  of 
this  species,  the  only  significant  point  is  the  failure  to  find  a single 
flower  bud  injured  in  a manner  to  cause  their  presence  to  be  suspected. 

a Bui.  10,  n.  s.,  Div.  Ent.,  U.  S.  Dept.  Agric.,  pp  82-83. 

& Twelfth  Census  of  the  United  States,  1900. 


STRAWBERRY  WEEVIL  IN  SOUTH-CENTRAL  STATES. 


61 


THE  STRAWBERRY  WEEVIL  IN  ARKANSAS. 

The  strawberry-growing  industry  in  Arkansas  is  a very  important 
one,  in  1899  the  production  of  this  State  being  nearty  four  times  that  of 
Texas  and  Louisiana  combined;  or,  in  round  numbers,  nearly  13,000,000 
quarts.  Three  sections  of  the  State  were  visited,  including  the 
two  leading  strawberry-growing  districts  which  together  produce  more 
than  four-fifths  of  all  the  strawberries  grown  in  the  State."  The  first  in 
importance  of  these  sections  comprizes  three  adjoining  counties  in  the 
northwest  corner  of  the  State-M^enton,  Washington,  and  Crawford. 
Van  Buren,  located  in  Crawford  Count}^,  the  southernmost  of  the  three 
named,  was  visited  on  April  27.  A single  adult  specimen  of  the 
strawberry  weevil  was  taken  on  a wild  blackberry  growing  by  the 
roadside,  but  in  the  strawberry  fields  the  only  indications  of  its 
presence  which  were  found  were  a few  scattering  severed  flower  buds. 
The  second  section  in  importance  in  strawberry  production  in  Arkan- 
sas is  located  in  White  County,  which  is  situated  a short  distance 
northeast  of  the  geographical  center  of  the  State.  This  county  in 
1899"  produced  one  and  a half  million  quarts  of  strawberries,  or  a 
quantit}7  a little  short  of  equaling  the  total  production  of  the  State  of 
Louisiana.  Bald  Knob  and  Judsonia,  two  leading  strawberry  shipping 
points  in  Smith  Count}7',  were  visited  on  April  25.  Many  strawberry 
fields  were  visited,  and  the  weevil  was  found  to  be  moderately  abun- 
dant near  these  localities.  The  destruction  in  the  many  fields  exam- 
ined was  estimated  to  range  from  5 to  25  per  cent  of  the  flower  buds, 
averaging  between  10  and  15  per  cent.  Along  the  roadsides  a small 
percentage  of  the  flower  buds  of  wild  blackberries  had  been  wholly  or 
partially  severed.  The  weevil  and  its  destructive  habits  were  found 
to  be  fairly  well  known  among  the  strawberry  growers  in  this  section, 
by  whom  the  weevil  was  reported  to  have  varied  in  abundance  from  year 
to  }Tear,  and  in  occasional  years  in  the  past  to  have  accomplished  con- 
siderable damage.  The  destruction  of  the  flower  buds,  as  mentioned 
above,  did  not  necessarily  represent  a proportionate  loss  to  the  grow- 
ers, as  picking  had  begun  about  ten  days  earlier,  and  berries  produced 
from  flowers  which  set  at  a later  date  than  the  writer’s  examination 
very  likely  would  remain  unpicked  owing  to  the  expected  falling  off 
in  the  market  demands.  The  third  locality  in  Arkansas  where  an 
examination  was  made  is  near  the  center  of  the  State,  1 mile  from 
Little  Rock.  An  hour’s  search  in  a strawberry  field  on  April  26 
revealed  a few  severed  buds,  while  not  a hundred  yards  away  wild 
blackberries,  which  were  very  common  along  the  roadsides,  had 
from  5 to  10  per  cent  of  their  flower  buds  destroyed.  The  only  adult 
specimen  of  the  strawberry  weevil  taken  in  this  vicinity  was  on  a 
blackberry  bush. 


“Twelfth  Census  of  the  United  States,  1900. 


62 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


VARIETIES  OF  STRAWBERRIES  GROWN. 

At  Alvin,  Tex.,  the  favorite  variety  among  the  strawberry  growers 
is  the  Klondike,  while  at  the  other  localities  mentioned  individual 
preference  seems  to  be  divided  between  the  Lady  Thompson,  Michel, 
and  Excelsior  varieties.  In  the  section  of  the  country  to  which  these 
notes  refer,  the  writer  has  never  met  any  strawberry  growers  who  use 
any  but  bisexual  varieties.  Arkansas  growers,  who  probably  suffer 
more  or  less  loss  every  year  from  the  strawberry  weevil,  should  be 
encouraged  to  introduce  suitable  early  pistillate  varieties,  as  the  insect 
in  that  State  threatens  to  cause,  occasionally  at  least,  considerable 
destruction. 


O 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ENTOMOLOGY  BULLETIN  NO.  63,  Part  VII. 

L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau. 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL  AND 
RELATED  AND  ASSOCIATED  INSECTS. 


THE  COTTON  STALE-BORER. 

BY 

A.  C.  MORGAN, 

Special  Field  Agent. 


Issued  February  9,  1907. 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE. 

1907. 


LETTER  OF  TRANSMITTAL. 


U.  S.  Department  of  Agriculture, 

Bureau  of  Entomology, 
Washington , D.  C.,  December  i,  1906. 

Sir:  I have  the  honor  to  transmit  herewith  a short  account  of  the 
cotton  stalk- borer,  prepared  by  Mr.  A.  C.  Morgan,  special  field 
agent  in  this  Bureau.  Altho  this  insect  appears,  as  a rule,  to  attack 
cotton  stalks  which  are  already  injured  or  diseased,  thus  causing  onl\ 
slight  damage  to  the  crop,  Mr.  Morgan  finds  evidence  that  healthy 
stalks  may  be  occasionally  attacked.  I recommend  the  publication  of 
the  paper  as  Part  VII  of  Bulletin  No.  63  of  the  Bureau  of  Entomology 
Respectfully, 

L.  O.  Howard, 

Entomologist  and  Chief  of  Bureau. 

Hon.  James  Wilson, 

Secretary  of  Agriculture. 


n 


CONTI:  NTS. 


Page 

Distribution - 63 

Host  plants , 63 

Life  history . 64 

Injury  and  economic  importance 64 

Natural  enemies 65 

Remedy 65 

Bibliography 66 


ILLUSTRATIONS. 


Page. 

Plate  III.  Fig.  1. — Adult  or  beetle.  Fig.  2. — a,  galleries;  b,  work.  Fig.  3. — 
Emergence  holes  of  adults.  Fig.  4. — a,  larva  in  situ;  b,  pupa  in  situ. 

Fig.  5. — a,  gallery  running  into  root  of  plant;  b , castings  behind  larva  ...  64 


in 


U.  S.  D.  A.,  B.  E.  Bui.  68,  Part  YU. 


C.  P».  W.  I..  February  0,  1907. 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL 
RELATED  AND  ASSOCIATED  INSECTS. 


THE  COTTON  STALK-BORER. 

( Ataxia  crypta,  Say. ) 

By  A.  C.  Morgan, 

Special  Field  Agent. 

During  October,  1905,  while  inspecting  cotton  fields  in  the  vicinity 
of  Yoakum,  Tex.,  the  writer’s  attention  was  attracted  by  the  great 
number  of  dead  stalks.  Examination  showed  that  these  stalks  con- 
tained larvae,  pup*e,  and  adults  of  the  cotton  stalk-borer  (. Ataxia 
crypta  Say). 

DISTRIBUTION. 

The  specimen  which  Say  described  in  1832  as  Lamia  crypta  came 
from  Louisiana.  Haldeman’s  specimen,  described  as  A.  sordida , came 
from  Alabama.  Leng  and  Hamilton  recorded  the  species  from  Penn- 
sylvania, Alabama,  Louisiana,  Texas,  and  New  Mexico.  In  Biologia 
Centrali-Americana  its  habitat  is  extended  to  Almolonga,  Mexico.  It 
has  been  reported  to  the  Department  from  Tucson,  Ariz. ; New  Orleans, 
La.;  Savannah,  Ga. ; Grant,  Fla.;  and  Round  Mountain,  San  Diego, 
Beeville,  Bexar,  Edgar,  Flatonia,  and  Dallas,  Tex.  During  1905  the 
writer  found  it  in  Texas  at  Yoakum,  Sublime,  Corpus  Christi,  Cotulla, 
Alice,  and  Victoria.  During  February  and  March  of  1906,  Mr.  W.  W. 
Yothers  collected  hibernating  adults  from  cotton  bolls  at  Athens, 
Brenham,  Navasota,  and  Calvert.  Tex.,  and  on  March  1,  1906.  the 
writer  also  obtained  specimens  from  bolls  at  Flatonia,  same  State. 

HOST  PLANTS. 

The  cotton  stalk-borer  attacks  a number  of  plants.  At  Tucson, 
Ariz.,  it  was  reported  on  Helianthus  and  Xanthium.  At  Savannah. 
Ga. ; New  Orleans,  La.,  and  Round  Mountain,  Tex.,  larvae  have  been 
found  boring  in  the  twigs  and  trunk  of  the  fig.  Mr.  E.  A.  Schwarz 
informs  the  writer  that  it  has  been  bred  frequently  from  the  stem  of 
Ambrosia,  and  one  report  of  the  borer  in  this  plant  was  received  by 

63 


64 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


the  Department  from  Edgar,  Tex.  On  March  1,  1906,  the  writer 
found  larvae  in  the  stems  of  Ambrosia  and  Helianthus  at  Flatonia, 
Tex.  It  has  been  reported  breeding  in  cotton  from  Bexar  and  San 
Diego, Tex.,  and  the  writer  found  it  in  October,  1905,  breeding  in  this 
plant  at  Yoakum,  Sublime,  and  Victoria,  and  in  November  at  Alice, 
Tex.  The  adult  has  been  reported  from  peach  and  apricot,  but  there 
are  no  records  to  show  that  it  injures  either  of  these  plants.  Leng 
and  Hamilton  state  that  specimens  were  found  boring  in  dry  twigs  of 
box  elder  (Acer  negundo)  and  hackberry. 

LIFE  HISTORY. 

Very  little  work  has  been  done  upon  the  life  history  of  this  species. 
The  egg  is  laid  upon  the  host  plant  and  the  larva  upon  hatching  bores 
into  the  bark  or  wood  of  the  plant,  where  it  feeds  until  full  grown, 
pupates,  and  finally,  when  adult,  cuts  its  way  out.  The  winter  is  very 
probably  past  in  any  of  the  three  stages  of  larva,  pupa,  or  adult,  for 
it  has  been  reported  by  Mr.  E.  A.  Schwarz  as  emerging  in  May,  1897, 
from  a stalk  of  cotton  cut  in  December,  1896.  In  October,  1905,  the 
writer  found  the  insect  in  cotton  stalks  in  all  stages  of  development 
from  the  very  small  larva  to  the  adult  ready  to  emerge  from  the  stalk. 

In  southwest  Texas,  where  the  winters  are  ver}7  mild,  it  is  very 
likely7  that  development  proceeds  slowly  all  winter  long,  except  in  the 
most  severe  winters,  when  it  would  probably  cease  for  a few  weeks. 

INJURY  AND  ECONOMIC  IMPORTANCE. 

Rarely  has  the  cotton  stalk-borer  been  reported,  and  in  no  case  has 
serious  damage  been  ascribed  to  it.  Altho  it  was  described  by  Say 
as  earty  as  1832,  no  mention  is  made  of  it  in  economic  literature  until 
1896,  and  since  that  time  only  live  short  notes  have  been  made,  all  of 
which  are  apparently  based  upon  Dr.  L.  O.  Howard’s  first  published 
notice  in  1896,  which  reads  as  follows: 

There  is  but  one  borer  in  the  stalks  of  cotton,  and  that  is  the  long-horned  beetle 
known  as  Ataxia  crypta  (Say).  It  is  occasionally  mistaken  for  an  enemy  of  the 
plant,  but  investigation fias  shown  that  it  lays  its  eggs  upon,  and  its  larvae  bore  into, 
only  such  stalks  as  have  been  damaged  by  some  other  cause,  such  as  rust.  It  follows 
injury  to  the  plant  rather  than  causes  it. 

The  rather  general  occurrence  of  this  insect  at  Yoakum,  Tex.,  in 
1905  has  made  it  seem  advisable  to  publish  this  more  extended  note. 
Twenty-six  fields  were  examined  in  this  locality,  and  showed  that  from 
5 to  10  per  cent  of  the  stalks  were  infested  by  this  insect.  One  Held 
had  20  to  25  per  cent  of  its  stalks  injured  by  the  borer.  It  is  to  be 
regretted  that  the  discovery  of  this  infested  locality  was  not  made 
earlier  in  the  season,  so  that  a more  conclusive  study  could  have  been 
made. 


Bui.  63,  Part  VII,  Bureau  of  Entomology,  U.  S.  Dept,  of  Agriculture 


Plate  III. 


The  Cotton  Stalk-borer  (Ataxia  crypta). 

Fig.  1. — Adult  or  beetle.  Fig.  2. — a,  Galleries;  b,  work.  Fig.  3. — Emergence  holes  of  adults. 
Fig.  4. — a,  Larva  in  situ;  b , pupa  in  situ.  Fig.  5. — a,  Gallery  running  into  root  of  plant;  b, 
castings  behind  larva.  Fig.  1 twice  natural  size;  figs.  2-5  two-thirds  natural  size.  (Original. ) 


LIBRARY 

UNIVERSITY  Of  ILLINOIS 
URBANA 


THE  COTTON  STALK-BORER. 


65 


As  has  been  stated  by  Doctor  Howard,  it  is  the  larva  of  the  borer 
that  works  in  the  cotton  stalk.  It  confines  its  attack  to  the  pith  of  the 
plant.  The  amount  of  injury  depends  upon  the  size  of  the  plant  and 
the  number  of  borers.  The  writer  found  one  plant  about  3 feet  high 
at  Yoakum  which  contained  eight  larvae,  and  which  showed  four 
emergence  holes.  The  twelve  borers  had  eaten  out  all  the  pith  from 
the  smallest  branches  to  3 inches  below  the  surface  of  the  ground  in 
the  tap-root.  The  small  twigs  were  only  thin  shells  and  crumpled  like 
paper  between  the  fingers. 

Nearly  all  infested  plants  showed  unmistakable  evidence  of  previous 
injury,  yet  the  comparatively  fresh  and  healthy  condition  of  a few 
stalks  points  to  the  probability  of  an  occasional  attack  upon  perfectly 
healthy  stalks.  In  the  field  showing  an  infestation  of  20  to  25  per 
cent  of  its  stalks  it  was  estimated  that  the  injured  stalks  had  borne 
at  least  80  per  cent  as  much  cotton  to  a stalk  as  had  the  uninjured 
ones.  If  it  is  true  that  the  borer  attacks  only  such  stalks  as  are  dis- 
eased or  otherwise  injured,  then  only  a little  damage  can  be  attributed 
to  it;  yet  the  borer’s  attack,  added  to  the  injury  due  to  disease,  must 
hasten  the  death  of  the  plant  and  thereby  lessen  the  number  of  bolls 
to  mature. 

NATURAL  ENEMIES. 

From  material  collected  at  Yoakum,  Tex.;  on- October  28  two  para- 
sites of  Ataxia  crypta  were  bred.  One.  Ileterospilus  websteri  Ashm., 
had  entirely  covered  the  pupa  of  A.  crypta  with  its  cocoons.  In  the 
majority  of  cases,  however,  this  parasite  had  spun  its  cocoon  after 
crawling  away  from  the  body  of  its  host.  Several  masses  of  these 
cocoons  were  found  with  no  trace  of  either  the  larva  or  pupa  of  A. 
crypta  visible,  and  in  one  instance  the  larvae  of  this  parasite  were 
found  in  a hollow  cotton  stalk  and  no  form  of  A.  crypta  near.  The 
second  parasite  belongs  to  the  genus  Etroxys  and  is  a new  species. 
There  is  some  doubt  that  this  species  is  a parasite  upon  Ataxia,  but 
since  it  is  parasitic  upon  beetles  and  its  pupae  were  found  in  a stalk 
bored  out  by  A.  crypta , it  is  here  placed  on  record  as  a parasite  of  the 
latter. 

REMEDY. 

If  at  any  time  the  injury  by  the  insect  should  become  serious  the 
numbers  of  the  borer  can  be  easily  reduced  b}r  destroying  the  infested 
stalks  early' in  the  fall.  The  time  of  destruction  must,  of  course,  vary 
in  different  localities,  but  it  should  be  as  early  in  October  as  possible 
for  the  latitude  of  Yoakum.  By  October  28  not  more  than  10  per 
cent  of  the  borers  had  emerged.  If  the  stalks  had  been  destroyed 
early  in  October  very  few  borers  would  have  escaped.  To  obtain  the 
best  results,  stalks  should  not  be  cut  but  plowed  out.  for  many  of  the 


66 


PAPERS  ON  THE  COTTON  BOLL  WEEVIL,  ETC. 


borers  go  2 or  3 inches  below  the  surface  of  the  ground  in  the  tap-root 
and  pupate  there.  In  regions  infested  by  the  boll  weevil,  if  the 
farmers  would  follow  the  directions  given  by  this  Bureau  for  the 
destruction  of  stalks,  the  cotton  stalk-borer  would  not  appear.  In 
regions  uninfested  by  the  boll  weevil  but  infested  by  the  cotton  stalk- 
borer,  an  occasional  examination  of  infested  areas  for  the  emergence 
holes  of  the  borer  or  an  examination  of  the  stages  in  the  stalk— which 
can  be  made  by  splitting  the  stalk  with  a knife — will  show  the  planter 
when  to  begin  plowing  and  burning. 

BIBLIOGRAPHY. 

1832.  Say,  Thomas. — Insects  of  Louisiana,  pp.  5 and  6,  and  Entomology  of  North 
America  (Le  Conte,  ed. ),  vol.  1,  p.  302. 

Original  description  under  the  name  of  Lamia  crypia. 

1847.  Hai.deman,  S.  S. — Trans.  Amer.  Phil.  Soc.,  vol.  10,  p.  56. 

A description  of  the  insect  under  the  name  Ataxia  sordida. 

1878.  Schwarz,  E.  A. — Coleoptera  of  Florida.  Proc.  Am.  Phil.  Soc.,  Vol.  XVII, 
p.  457. 

1883.  Le  Conte,  J.  L.,  and  Horn,  G.  H. — Classification  of  Coleoptera  of  North 
America,  p.  329. 

Authority  for  present  nomenclature. 

1885.  Bates,  H.  W. — Biologia  Centrali- Americana,  vol.  5,  p.  347. 

A short  note  upon  synonymy. 

1896.  Howard,  L.  O. — Bui.  33,  Office  of  Experiment  Stations,  p.  347. 

First  economic  note. 

1896.  Leng,  Chas.  W.,  and  Hamilton,  John. — The  Lamiinae  of  North  America. 

<Trans.  Am.  Ent.  Soc.,  Vol.  XXIII,  p.  143. 

1897.  Howard,  L.  O. — Farmers’  Bui.  No.  47,  U.  S.  Dept.  Agric.,  p.  28. 

1899.  Sanderson,  E.  D. — Cotton  Planters’  Journal,  May,  1899. 

1902.  Sanderson,  E.  D. — Insects  Injurious  to  Staple  Crops,  pp.  197,  198. 

1905.  Sanderson,  E.  D. — Farmers’  Bui.  No.  223,  U.  S.  Dept.  Agric.,  p.  17. 

1906.  Sanderson,  PL  D. — Bui.  No.  57,  Bureau  of  Entomology,  IT.  S.  Dept,  of  Agric., 

p.  38. 


O 


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